## Supervised Learning & Its Types: Machine Learning Essentials

Welcome back, machine learning geeks! Let’s delve deeper into our journey of mastering machine learning. In the previous article, we looked at both informal and technical definitions of machine learning.

We also looked at the two major types of machine learning algorithms, A) supervised machine learning algorithms, and B) unsupervised machine learning algorithms. We also mentioned reinforcement learning and recommender systems, but won’t spend as much time there.

Let’s jump in!

## Introduction to Supervised Learning

Supervised machine learning algorithms are used when you:

1. Have a set of known, correctly labeled data
2. Are looking to predict a continuous value output

Let’s visualize by looking at a digital marketing example.

Perhaps we are digital marketers looking to forecast or predict how much time and effort we’ll need to spend on outreach and content promotion for a particular webpage and target ranking.

Say we’ve gathered some data about website pages with:

• Their rank for a given keyword
• The amount of unique linking domains pointing to each page

Such a distribution of data might look like the below. It demonstrates a trend, but right now, we don’t have a single linear function that will “connect all the dots”.

This is a great example for the first major subdivision of supervised machine learning algorithms:

## Regression Learning Problem

Off the cuff, there are a couple of different ways in which we might try to solve this problem. Both solutions involve using the “labeled” data to predict a line of best fit, which, on the whole, minimizes the distance between the line and all the points. If we have a simple slope, predictions could be precarious at best, and misrepresentative on the other end of the spectrum.

We could also instruct our programs to fit a quadratic equation to the data (read: not a straight line.) In our slightly altered example here, the difference could be significant.

At this point in time, we won’t focus on whether we should pick a linear or quadratic line for the regression output. However, it is worth noting that the two different methods could yield widely varying results.

Say we wanted to get a webpage ranking in position 5 for this given study, a linear example would have us preparing to secure links from ~180 unique domains. If we decided on the quadratic solution, we could be looking at significantly less effort, perhaps ~125 unique linking domains?

## Classification Learning Problem

Insert smooth segue here and please forgive my lazy writing at this time. 🙂

The next major subdivision of supervised machine learning algorithms is known as a classification problem. Let’s use another example.

We are analyzing a large user study of an Amazon Alexa Skill in development. Perhaps we are classifying a particular interaction with the skill by success or failure (1 or 0), and plotted against the measured spoken word count for the given interaction.

Visualized, this data might look like the below.

In this example with (shockingly 🙂 ) clean data, we might want to guide development efforts in providing the best sample phrases/interactions for the skill. Perhaps, we would want to measure the probability an interaction four (4) spoken words long will be successful. This is known as a classification learning problem.

Above, we examined only one factor in determining a probability. However, we aren’t limited to examining just one parameter.

Let’s consider the following, perhaps we are an e-commerce retailer or digital business. A frustration for many marketers is the “one and done” (self explanatory) customer that represents minimal customer lifetime value for the brand.

It would certainly behoove us to identify these customers and provide them with specialized messaging or a compelling promotion offer to keep them engaged and transacting with the brand.

Below, we could have a sample data set to which we fit a line, and thereby predict based on a certain age and AOV (average order value) profile whether a particular transaction is likely or not to be a “one and done” consumer.

In practice, we could potentially use a number of inputs to help solve machine learning problems. There are even methods to use an “unlimited” number of inputs- support vector machines. But only a tease for now!

## Wrap-Up

Our first major classification of machine learning algorithms is supervised learning! In supervised learning, we assist the program by supplying the correct answers in part, and then mandating the program supply correct values via regression or classification, the two major categories of supervised machine learning problems.

Moving forward, we’ll dive deeper into one variable linear regression (dare we say the hello world of machine learning?) as well as fleshing other key concepts and methods. If you’re interested in this, you might also be interested in learning PostgreSQL, how to develop Alexa skills, or algorithmic trading. Take care.

## What is Machine Learning?

Hello there, fellow Machine Learning (ML) students! Welcome back to our crash course in starting machine learning from an absolute beginner’s perspective.

In our previous article, we covered an introduction to Machine Learning, answering several key questions:

• Where is machine learning used in our lives?
• Where did machine learning come from?
• Where is machine learning headed?

Forging ahead in our learning journey, we’ll introduce some definitions of machine learning and look at the major types of machine learning applications.

## Machine Learning (ML), A Casual Definition by Arthur Samuel

Our first definition, teased in the last article, follows:

Machine learning is the practice of giving computers the ability to learn without being explicitly programmed to do so.

## More on Arthur Samuel & Why His Definition on ML Matters

If you’re like me, you might not have heard of Arthur Samuel. Who is he, and why does his opinion matter in the fields of artificial intelligence and machine learning?

Arthur Samuel was a pioneer in artificial intelligence and computer gaming fields. In 1959, he coined the term “machine learning” as a founding father in the field. That’s why he’s important! Let’s also look at a more formal / scientific definition.

## A More Formal Machine Learning Definition

Tom Mitchell, of Carnegie Mellon, offers a definition with more structure.

• A well defined learning problem follows
• E * T = P
• Note: His definition does not include mathematical operators. I’m taking a large liberty to insert them myself. ¯\_(ツ)_/¯
• Experience (E) placed against Task (T) is measured by Performance (P)

Here’s a further example:

Example: playing Go.

E = the experience of playing many games of Go.

T = the task of playing and winning Go.

P = the probability that the program will win the next game.

## Major Categories of Machine Learning Algorithms

If you judge by press coverage of ML as I have, it appears to be a nebulous field. (In all fairness, it may still be.) However, there is structure we can take in learning ML. There are two types of machine learning algorithms:

• Supervised learning algorithms
• Unsupervised learning algorithms

There are a couple of other prominent types of machine learning algorithms as well: reinforcement learning and recommender systems.

## Wrap-Up

Congratulations, we’ve cleared a very gentle introduction to machine learning, and it’s novice/high level definitions. I look forward to learning more with you, dear reader! Our next articles will cover a bit more detail about the two major ML algorithm types: supervised learning, and unsupervised learning. Until then, look after each other.

## An Introduction to Machine Learning

Howdy! This is an abrupt interruption to our regularly scheduled programming of SQL lessons, Amazon Alexa Skill development and Algorithmic trading. For those readers who don’t personally know me, I’m on a quest/streak to level up as a technologist.

Getting around to the point, I’ve been taking self-paced courses in varying forms to learn, apply and share new skills. However, I’ve heard the Coursera Stanford class in Machine Learning taught by Andrew Ng recommended so widely, I’m just going to doggedly sprint a marathon. I’m starting almost a week behind, working a busy job, trying to have a social life, and many other things…but darnit, I’m going to give this class my best shot. Hopefully I finish. 🙂

Okay, over-sharing complete. Let’s jump into a brief introduction of Machine Learning.

Machine learning, according to Andrew Ng (Chief Scientist at Baidu), is the science of getting computers to learn without being explicitly programmed.

## Where is machine learning used in our lives?

Machine learning is employed a large number of actors. Here are a few examples:

• Search engines, such as Bing, use machine learning to process MASSIVE amounts of data to quickly rank web pages in order of relevance, with limited human intervention.
• Social networks, such as Facebook, use machine learning to recognize your friend’s faces for auto-tagging capabilities.
• Email providers such as Apple Mail may employ spam filters that continuously learn to protect your inbox, your computer, and most importantly, your sanity.
• Tech companies such as Amazon use natural language processing (NLP) to create conversational experiences and transactions with skills and services.
• Entertainment companies such as Netflix use self-learning algorithms to recommend compelling new films and TV shows for those of you who binge watch

## Where did machine learning come from?

Machine learning originated from a computer science field known as artificial intelligence. Long seen as a pipe dream from Star Trek (crass and careless reference, I know), machine learning is a practical and attainable segue to artificial intelligence, or machines and programs that contain some degree of self awareness.

This capability is a relatively new, yet a rapidly exploding field that grows as mathematical, statistical, hardware and software capabilities continue to compound and improve.

What follows is a better question still.

## Where is machine learning headed?

Machine Learning in the future could look like a few different things (but not limited to this list, obviously!):

• Predictive and preventative applications in engineering, medicine, and security
• “Load bearing” performance in complex tasks, such as architecting, coding and programming self-driving cars
• Coordinate machines and programs that study our behavior at our request and perform tasks, such as performing spring cleaning
• Assistants or programs that are intelligent – able to optimize and independently solve problems on our behalf

## Wrap-Up on the Machine Learning Introduction

That wasn’t so bad was it? We’ll follow soon with a more formal definition of Machine Learning and its various tranches of study. Cheers all.

## The LIKE Statement: SQL Statement Fundamentals

Howdy folks! We are overdue for another installation of SQL learning. I’ve slept a few times since the past couple of articles on how to learn SQL. Previously, we talked about the IN Statement, BETWEEN statement, and ORDER BY clause.

In this article, we’ll learn how to execute the LIKE statement in SQL queries. Let’s jump in.

## About the LIKE Statement & Why it’s Important

Have you ever worked with a data set that’s overwhelmingly large  or complex? Or overwhelmingly large and complex? Sometimes, you need to find data, but can’t recall the exact string or values for a lookup. Or, perhaps, you’re working with a messy data output from say, Google Keyword Planner that groups a range of close variants into one value?

Say you’re looking for values related to designer clothing and designer clothes. Without a better solution, the most probable solution for you is to do a bunch of sorting, filtering, classifying and other data sleuthing at great expense to time and sanity.

The LIKE statement exists to help with the debacle of only having / knowing  part of the lookup criteria you need, courtesy of pattern matching.

PostgreSQL and many other SQL engines/platforms support the LIKE statement, which functions a bit like the below. (Pun not intended.)

SELECT keyword, search volume

FROM table

WHERE keyword LIKE ‘cloth%’

The above tells pgAdmin / PostgreSQL to get the keyword and search volume columns from table, where the keyword values match values that begin with ‘cloth’ and are followed by anything else, the percent sign. The combination of calling out a text string with an operate is known as a pattern.

When you execute the LIKE statement in a SQL query, pgAdmin will begin reading through the table rows to see if the pattern you’ve specified returns any matches. For the season marketing technology folks, this functionality sure does resemble regex in some ways.

However, there are some differences.

• Here, instead of the * character being wildcard, the % sign serves as a wildcard matching all characters.
• If you want to match a single character, the underscore character is used.

## LIKE Statement Syntax & Examples

Let’s try some examples. Below, we’ll call on the faithful DVD rental practice database, and run a query for customers that have first names like Jen. (Jennifer, Jenny, etc.) Our below code produces the following result.

SELECT first_name,last_name

FROM customer

WHERE first_name LIKE ‘Jen%’;

That being considered, there are other ways we can use the like statement. Above, we used a wildcard to match any endings to a particular string.

Conversely, we could execute a SQL query that specifies a certain ending value, with the wildcard preceding. If we extend that example to such a query below, we should see the following result:

SELECT first_name,last_name

FROM customer

WHERE first_name LIKE ‘%y’;

Above, we’ve flipped the tables so we capture every possible beginning condition under this pattern. Also important to note, the patterns aren’t limited beginnings or ends. You can use this wildcard in the middle, etc. Consider the following:

SELECT first_name,last_name

FROM customer

WHERE first_name LIKE ‘%er%’;

Now, on top of all this awesomeness, realize we’ve been using it as a matching filter. We can also employ the NOT LIKE syntax to exclude values meeting the pattern we’ve specified.

Let’s mix things up a bit. We mentioned a second type of pattern matching character that we haven’t used yet: the underscore.

SELECT first_name,last_name

FROM customer

WHERE first_name LIKE ‘_her%’;

Above, we’ve made a similar ask. However, instead of requesting all possible matches, we’ve mandated SQL only return the ‘er’ string that begins with ‘h’.

To throw you a quick curveball, it’s worth noting the LIKE statement is case sensitive in its matching. Could be bad, could be good, could be neither. However, there’s a way for you to force case insensitivy on the queries. The difference in your statement appears relatively minor. Instead of using a function that calls LIKE or NOT LIKE, you’ll use ILIKE.

## Wrap-Up

Hope you found this useful! Stay tuned for more SQL learnings and application. If you’re new here, visit the page on how to learn SQL. If you’re interested in more educational material, check out our ongoing series of how to develop Amazon Alexa voice search skills, and getting started with algorithmic trading. Cheers!

## Building an Interactive Alexa Quiz Skill, Part 2

Disclaimer: this was typed late at night on a tired mind. Please excuse typos, convention errors, and generally poor writing. 🙂

Howdy, Alexa nerds! Welcome back to our journey in learning Amazon Alexa Skill Development. Quick funny aside, would you care to guess my most common use of the Echo? It’s to play looong Spotify playlists that are basically background noise to help our new dog when Hannah & go to the gym or meet friends. Anyway!

Let’s jump back in. The previous article covered setting up an AWS Lambda function for the Alexa Skill Service. Now, we’ll be working more with the Skill interface. See below for the conceptual overview, or an early article on building Alexa skill interfaces for a basic fact skill.

## Working in the Amazon Developer Console: Alexa Skills Kit

You probably know the drill now, log in to the Amazon Developer console. Once you’ve logged in, select the “Alexa” menu item from the home screen, then choose the “Alexa Skills Kit” Option.

If you’ve previously published or started development of skills, you should see them listed on this screen. Now, click, “Add a New Skill”. We should be looking at a very familiar screen here. 🙂

• Language (assuming you’ll leave the English US default here)
• Name of the Skill displayed in the Alexa app and store
• Invocation name users will speak to start your skill

Click Save and Next to proceed.

## Working with the Interaction Model

Here comes the tough part, more copy and paste! Okay, sarcasm and humor doesn’t always translate well via text. We’re going to continue to lean fairly heavily on Amazon’s examples here to get ourselves familiarized with the more advanced concepts of intent schema and slot types.

That caveat aside, head back to the files we originally downloaded, but this time, we’re interested in the speechAssets folder and its contents:

• json
• Sample utterances (text document)

First, let’s open up the Intent Schema JSON file in our text editor of choice. Below, a look at what you should approximately be seeing. Copy and paste the entirety of the JSON file into the Intent Schema field of the Interaction Model tab.

## Audible: Our First Encounter with Custom Slot Types

Alright, no smooth segue here. We’re having the first encounter with what’s known as custom slot types.

If you were to try and save the skill progress so far, you’ll receive an error message from the developer console that says something like, “Error: There was a problem with your request: Unknown slot type ‘LIST_OF_ANSWERS’ for slot ‘Answer’. Why is that?

If you take a closer look at the Intent Schema JSON file, you’ll notice that  most of the intents are built-in Amazon intents. E.g., “intent”: “AMAZON.RepeatIntent”. The “AnswerIntent” looks nothing like the built-in Amazon intents. Instead, we see a name, “Answer” and type, “LIST_OF_ANSWERS” that was so delicately referenced in the error message.

So how do we remedy this situation? We use the information presented to us in the error message and the JSON file to work our way over this issue. You’ll likely note under the custom slot types mentions “Enter Type”.

Match that information up with our error message and the JSON code, and we’ll enter, “LIST_OF_ANSWERS”. In the values section, we’ll enter on separate lines: 1, 2, 3, and 4. I’ll note here for clarity, that this essentially corresponds to the A/B/C/D multiple choice functionality of the quiz. We’ll see this in greater detail in a bit.

Okay, click “Add” as highlighted above, then click “Save”. Next, return to your files and open up the Sample Utterances text file. You should see something like the below.

You’ll note it’s quite a bit different than the previous, simple, fact-dispensing Skill we previously built. Take note of the {Answer} sample utterance. These are the pieces of dynamic input and interaction coming together into an Alexa Skill. We’ve defined a custom interaction outside of Amazon’s standard functions, and specified a range of acceptable answers the user can give us. That whole structure meets the user experience here, called in by the {Answer} slot name and custom slot type.

Enough conceptual babble. Copy and paste the sample utterances text into the developer console! Click Save beneath the sample utterances, and click Next.

## Continuing the Skill Interface Build-out

Alright, so far, we’ve accomplished the following:

• Provided basic skill information about our new skill
• Specified details about the interaction model, including;
• Intent Schema
• Custom Slot Type
• Acceptable/specified values for the custom slot type
• Sample utterances

Next, we need to fill in some simple but crucial configuration details. Remember the ARN we generated by setting up the AWS Lambda function in the previous article? You need it here. Below you can see:

1. I’ve selected the recommended endpoint type of AWS Lambda ARN
2. Selected my geographic region of North America and,
3. Pasted in the full ARN

I’m not going to work with account linking yet, because honestly, it looks really darn complicated and its well past midnight as I type this. Soon. 🙂 Click next and proceed to the testing tab!

In the testing tab, you should first see that the skill is enabled for testing on your account. You can:

• play back responses from Alexa in the voice simulator to test pronunciation, etc
• More importantly, use the service simulator to run a sample utterance, and see if your skill actually works.

Above, we can see the response to our sample utterance asking SEO Quiz returns as expected. Woohoo! Also, did you know the Alexa voice simulator automatically bleeps out most curse words? Did you know you can kind of work around that by putting extra vowels in the word? I digress. (It’s almost 1 am writing this now, productivity on the rise!) When you’re satisfied, click Next.

We’re getting close! Time to enter some publishing information. I’ll leave the first few sections to you: Category, Sub-Category, Testing Instructions, Country/Region availability, Short and Full skill descriptions.

Now, in the example phrases, I provided some updates to the sample utterances, namely to the starting Intent. Below, see the example phrases of “Alexa open SEO Quiz” and so forth. The “gotcha” here that set me back on my first skill is that the example phrases must be derived from your sample utterances.

Upload your 108×108 and 512×512 pixel icon images, click Next and submit the requisite privacy & compliance information. Done!

## Wrap-Up

So, we’re mostly done, not completely done. The part for usto do now is customizing the template code in your AWS index.js file. Ideally, I would prefer a more eloquent closing, but it’s late, will have to wait for another time. Look after each other.

## The IN Statement: SQL Fundamentals

Howdy, budding SQL masters! It’s been a minute since the last SQL post! I’ve taken some time to devote to Alexa Skills, some other personal housekeeping, and adopting a dog with my wife!!

Last time we talked SQL, we learned the BETWEEN statement to hone in on the exact values we wanted for a SQL query. Prior to that, we looked at the LIMIT statement to get a small return data sample and also working with ORDER BY to take sorting and filtering into our own hands.

Today we’ll be working with the IN statement.

The IN SQL operator is a companion to the WHERE clause to see if a value matches any value in a list of values. Sounds something kind of like VLOOKUP’s, yeah? The syntax of an IN statement might look like:

value IN (value1, value2)

The expression in your SQL query will return true if the value(s) you’ve specified in the query match any value in the list you’re referencing.

### Sub-queries: Using the IN Statement with SELECT

The list of values is not limited to a static number or list of strings. That is, you can be a bit more dynamic and free-flowing with your query by getting the value via a SELECT statement.

This is also known as a sub-query. To illustrate, the syntax might look like:

value IN (SELECT value FROM table)

### NOT IN: Not Making Fetch Happen

The IN statement has a similar corollary as the BETWEEN statement- a NOT modifier. So, we can take the inverse of a statement. (Drawing on some experience in data analysis, this can just as, if not more useful than the original statement!)

value NOT IN (SELECT value FROM table)

## Sample SQL Queries for the NOT IN Statement

Alright, let’s run some sample queries using the IN statement! Here’s our first go, working again with the ever-present dvdrental sample database. Below, we are selecting rental information for customers matching only a certain ID cohort (think perhaps loyalty group?), with a few columns and sorting by descending order for the return date:

SELECT customer_id,rental_id,return_date

FROM rental

WHERE customer_id IN (1,2)

ORDER BY return_date DESC;

Below, we see our results returned as intended!

How about our corollary? If we want to add the NOT IN modifier, it’s as straightforward as you would imagine.

FROM rental

WHERE customer_id NOT IN (1,2)

ORDER BY return_date DESC;

Above, we again receive the desired result. I believe we also get a lesson in the importance of clean data here, as blank values are presented first. Let’s try one more sample query, just for kicks. We’ll switch it up ever so slightly, now working with the payment table.

SELECT city_id,city,last_update

FROM city

WHERE country_id IN (44,82,60)

ORDER BY city ASC;

Above, we’ve demonstrated that we don’t necessarily need to display a column we use in the query (country_id) and have sorted by city name in ascending order.

## Wrap Up

So why the IN statement? At face value, it seems rather simplistic among SQL clauses we’ve explored thus far. Let’s consider the following.

The IN statement allows us to avoid a messy swath of values courtesy of BETWEEN (if we’re working with a proper large data set), or daisy chain list of a bunch of equals OR statements. Here’s another plus, it’s thought by some that pgAdmin / PostgreSQL will execute the IN query faster than the list of OR statements.

Alright, that’s it for today’s article. If you’re like me and need a quick refresh, revisit our page on Learning SQL that contains all the topics we’ve covered so far.

## How to Build Your First Amazon Alexa Skill, Part 1 – The Skill Service

Introductory Disclaimer: AWS is changing, and changing fast! Between developing my first skill in mid-January 2017 and now going back to learn more / teach, quite a lot has changed in the AWS developer areas. All that to say is that I’ve already had to cobble screen shots together to make this article work, and the details could quickly become outdated. I don’t really intend to update this frequently, once I’ve completed my learnings. Apologies!

Welcome back, Amazon Alexa geeks! First, thanks for both your patience and kind feedback on the process of building your own Alexa and testing your DIY Alexa. Honestly, that was one of the hardest challenges I’ve had since first learning HTML / CSS coding back in college. (Thanks Raspian / Linux command line…)

Today, we’re getting back into actual Alexa skill development. We’ll be building your first (my second) Amazon Alexa skill for use on Echo and other devices.

Side note: I have previously developed an unremarkable skill, Silly Marketing Strategies, but I want to start fresh to:

1. A) do it better, and,
2. B) take a first stab at incorporating analytics capabilities into Alexa skills.

Without further ado, let’s get started with a conceptual overview to how Alexa skills work, and where developers (us!) play.

## Quick Concept Introduction

First, let’s look at a simplified process of you using an Alexa skill:

• You’ll say something like, “Alexa, play Road Trip Country Playlist on Spotify”
• The Echo, Fire TV, Raspberry Pi or other hardware takes in the audio and routes it into software/programs
• The Alexa Skills Kit Interface employs speech recognition and natural language processing/understanding to convert your speech into text strings, then to code
• The Skill service, facilitated by AWS Lambda processes the text strings against it’s suite of skills and programs, and outputs code,
• Which is fed back through the programs to hardware and to a lovely voice response, something like, “Resuming your queue…”

That’s the front end experience. As a developer, we’ll hone in toward the “last” two parts of user experience. In that frame of reference, we start at the logic of our program, working “backwards” to handling user input, and the desired result.

## Setting up AWS Lambda

Are we there yet? Okay, for real this time, let’s hop into code…by pulling up 2 URLs and logging in:

In the AWS console, you should see a screen like the below. First, update your region (top right) to US East, N. Virgnia. Why, you might ask? It’s the only region (currently, Mar. 2017) that supports Alexa.

Next you need to select Lambda from the list of AWS services. It should be readily available on your screen. Mine will likely look a bit different from having used it already. 🙂

If you’re a first-time Lambda user, you’ll likely see a welcome/splash screen that resembles the following:

You’ll have the option to select a blueprint (optional). You should be able to click next, or, there should be an Alexa skills kit SDK fact skill option you can select.

Moving along, when you launch Lambda for the first time, you’ll need to configure triggers. Below, you’ll want to select the Amazon Skills kit, and click, “Next”. Why are we configuring triggers for functions? Because our Alexa Skill is event-based, and only triggers when an event pertaining to it occurs.

You should now land on a Configure Function screen. These are the baby steps to making a skill! Give the skill a name and description. We’ve used SpaceGeek as values below, since we’ll be using the SpaceGeek template at first. Also, always select Node.js 4.3 for Alexa Skill Development.

Beneath the basic naming and settings is a Lambda function code section. Choose the “Upload a .ZIP file” option. Remember all the files we downloaded in our first article? You’ll need to go the SpaceGeek folder, src subfolder and zip the contents (shown below) and upload accordingly.

Note: It’s March 2017, I started in Jan. 2017 and the original tree /Github URL has already been deprecated. Zoinks, it’s moving fast!)

After you’ve uploaded the file, you need to create a new role from templates (beneath the file upload you just completed.) Feel free to name the role whatever you like, but the important detail here is that you select the S3 object read-only permission option under the policy templates dropdown selection.

Finally! You should be able to click, “Next” and clear this screen. You should see a review screen confirming the selections you’ve made. Click, “Create Function” and proceed! You should land within the Function itself. Since my new experience was already spent, here’s what the equivalent screen looks like, for Silly Marketing Strategies.

Last thing you’ll want to do is copy the ARN into a text file, word document, etc. for safekeeping down the line. You’ll need it soon.

## Wrap Up

Alright, we made a ton of progress in today’s article! I was hoping to make more progress, but the process of organizing, documenting, processing and writing is quite time consuming. It’s now 1 a.m. local time for me, and I need sleep for a long day at work tomorrow! We’ll be back very soon on how to work on the Skills Interface (utterances, logic, etc.) in more detail to publish your first skill! If you’re new or need a refresh, here’s our running list of articles on how to learn Amazon Alexa Skill development.

## How to Build Your Own Amazon Alexa with a Raspberry Pi

Howdy, it’s been a minute since my last post on Alexa Skill Development. I left us hanging, as I mentioned in one of my previous SQL posts, work craziness, sickness, and general life stuff happening imposed a brief, involuntary hiatus on writing.

Enough self talk to make future self feel better. Let’s build our own Amazon Alexa with a Raspberry Pi! What a step up from our previous articles. 🙂

But first! A couple of notes: This is NOT necessary for you to do in learning Alexa Skill Development. You can use a regular Echo instead of this expedition into Computer Homebrew 102. Also, I developed my first Alexa skill without an Echo or comparable device at all. One more thing, this is a long post that is both deep and wide ranging. Don’t say I didn’t warn you.

## 1. The Materials List

To get started, you’ll need a few things:

1. Raspberry Pi, version 2 or later
2. Power source
3. Micro SD card (Recommended at least 8 gb in storage size)
4. Speaker with a line-in 3.5mm cable (or headphones of similar line-in spec)
5. USB microphone
6. Keyboard and Mouse
7. HDMI cable to connect to a monitor or TV
1. Obviously, you need a monitor or TV. 🙂

A few notes on the Raspberry Pi: I recommend you get a pre-assembled kit, for time and convenience, if nothing else. I previously purchased from CanaKit on Amazon, and have been pleased with it. If, for some reason, you are building your own or need to reformat, the two articles below from RaspberryPi.org are simple, fast instructions to get you up to speed.

Formatting a MicroSD card 32 GB or less:

https://www.raspberrypi.org/documentation/installation/noobs.md

Okay, we’re going to proceed assuming that you’ve taken care of the above, and have successfully booted your Pi, connected all requisite hardware, connected to the internet, and so on. Below is where I’m at.

## 2. Installing Other Utilities

Another note here, it is possible to SSH (read: a bit like Microsoft’s RDP remote desktop application, but command line style) your way into the Raspberry Pi. I will not be doing that. This may sound a bit silly, but I don’t have a multi-screen dock for my laptop (capped at 2), and I’m happy for the Pi and other monitor to be a standalone computer. (Perks of a wide desk.) Also, the Wi-Fi USB card I’m using is very slow at the moment. Also, an edit after I’ve written this post offline: Linux-esque command line work is a royal pain in the you-know-what. Remarkable computing has advanced to where it is today. More on Raspberry Pi intricacies later.

Enough of my discourse, let’s continue setting up our Raspberry Pi / DIY Alexa to-be. Task time.

Navigate to your Pi’s command line module.

1. We’re going to update the GET. Type:
1. sudo apt-get update (Pro tip: don’t misspell sudo as I’ve laughingly done on the first try.)
2. In the new line created by default, type: clear and hit enter. This will clear your command line.

## 3. Registering Your Raspberry Pi as an Alexa Voice Service Device Type

Once you’ve logged in, click on the Alexa navigation item, then click “Get Started”. You should land on a page that has a “Register Product Type” drop-down. Select Device and continue.

You’ll be taken to a new screen / process to create a new device type. Choose and type your  device type ID and display name. For ease of process here, I’ve used the same value for device type ID and display name.

Once you’ve selected your ID and name of choice, click next. Now we need to create a new security profile. Click the dropdown menu that reads, “Select Security Profile” and click, “Create New Profile”. If you’ve filled out all the fields properly, you should have the option to submit this device / product. Hooray! Below is what I see after I submit the new device.

Create a Security Profile Name and Description of your choosing and click “Next”.

You’ll now see a new screen with your created security profile. Below, you should see some tabs such as, “General”, “Web Settings”, “Android/Kindle Settings”, and so forth. Click on “Web Settings” and then click “Edit”.

You should now be able to edit the “Allowed Origins” and “Allowed Return URLs” fields. Enter the following values into each of the fields, respectively:

1) https://localhost:3000

2) https://localhost:3000authresponse

Once you’ve entered the above values, click “Next”.

• Upload an image (I used this one, they’re picky about sizing)
• Choose a category (I selected “Other”)
• Provide a short description to your pleasing
• Select “No” for plans on making product available to general public
• Select “No” for product directed to children

Click “Next” to proceed. The next screen asks about applying for access to Amazon Music. I’m selecting “No” for the purposes of this exercise.

## 4. Enable Login With Amazon for your new Device / Product

Sweet! After you click, “Submit”, you should see the below. Now head over to the “Apps & Services” section, and select the “Login with Amazon” item, once the Apps & Services screen has loaded.

From the drop-down menu of existing security profiles, select the profile we just created. You’ll need to enter a consent privacy notice URL and a consent logo image. Because we’re doing anything public facing, you can enter any URL you’d like here. For the image, I used the same image from the device creation process. Click “Save” and let’s keep moving.

Upon a successful save, you should see a table with a column labeled “Oauth2 Credentials”. Click, “Show Client ID and Client Secret”, copy and save the information somewhere safe. Next stop, Raspberry Pi.

## 5. Install the Application on Your Raspberry Pi

Flip back over to your Raspberry Pi and type the following two bullet point texts as unique lines into command line.

• cd Desktop
• git clone https://github.com/alexa/alexa-avs-sample-app.git

It should take a minute or two to process, and you should see the below.

Next, type the below point texts as unique lines into command line:

• cd alexa-avs-sample-app/
• nano automated_install.sh

After returning the two above lines, you should see something like the below. Remember what we entered in the Developer Console a few steps ago? You’ll need this information here. (Highlighted boxes.) Update from 2/25/2017: I actually had quite a bit of trouble with this step. Linux command line / text emulator is not my friend yet. The trouble I had here was making and saving my changes to the below. However, the program is surprisingly helpful! It will prompt you to verify credentials before install proceeds.

After you’ve made the appropriate changes, command line language of CTRL + X should help you save the changes. Close out the command line window and re-open. Type the following bullet texts:

• cd Desktop
• cd alexa-avs-sample-app
• . automated_install.sh

When prompted for the AVS + Raspberry Pi License and Agreement, obviously answer and/or “y” to proceed, and answer yes and appropriate and desired throughout the setup process. E.g., you’ll be asked about language preference, audio input settings, enabling wake word detection, and so forth. (It takes anywhere from 30 min to 1 hour.)

Once the install runs, it’s time to start the Alexa service!

## 6. Running the Alexa Service / Finishing Touches

To test and run the Alexa service, we need 3 command line terminals open. The command paths for these are at the end of the install. (As I type this, the latest install on my Pi is approaching 45 minutes, so I’ll have to give you the bare bones for now based on past tests and some generous documentation.

The first terminal will set Alexa up to be listening on port 3000 (remember the local host URLs from earlier?) The second window deals with setting up a Java client and logging into Amazon with the Security profile we set up. Logging in and confirming will enable you to initiate the connection to Alexa, paving the way for the third terminal, which enables the wake word detection and actual running of the Alexa service. Woohoo! I’ll update with examples later.

### Update — 2/25/2017:

So, the whole process took a looooong time. At about 3 am of the night I wrote / finished this post, the Pi finally finished unpacking and installing everything. Below is our success confirmation! I’ll be testing this evening…

## Wrap-Up

Goodness, what a ride, if you stuck it through the whole article. You could do this, or just get a darn Echo. After all this, I recommend you buy an Echo. 🙂

Other miscellaneous updates from 2/25/2107: By the time I got to the wrap up, it was 3:30 in the morning, yikes! I wasn’t feeling very descriptive, nor was I yesterday either. This was an incredibly long process that took several days from start to finish. Was it worth it? Yes. I’m still going to test the capabilities tonight and hopefully have some follow up’s in the coming days. Will I be primarily using an Echo moving forward? Yes.

## The BETWEEN Statement: SQL Statement Fundamentals

Hey there, folks! Welcome back to our journey in learning SQL. Our last few of posts covered the ORDER BY clause, LIMIT statement and the COUNT function. (See full list of SQL tutorials here.)

Today, we’re going to cover the BETWEEN statement. This is the start of some deeper material. In addition to the BETWEEN statement, we’ll also soon be covering IN and LIKE statements.

The BETWEEN statement (rather, operator) is used to match a value against a specified range of values. Maybe we want to get transactions between a certain dollar amount.

For example, value BETWEEN low AND high;

More about the BETWEEN statement. If the value is greater than or equal to the low value and  less than or equal to the high value, the expression returns true, or vice versa. Also, the BETWEEN operator can be rewritten by using the greater than or equal to ( >=) or less than or equal to ( <=) operators as the following statement.

value >= low and value <= high;

One other way to think about the BETWEEN statement is that takes two WHERE statements and lumps them into one. Think back to the WHERE statement, as we would say first:

SELECT column1 FROM table WHERE column1 >= 2 AND column1 <= 7;

## To BETWEEN or NOT BETWEEN

Conversely, you can extend the usage of the original BETWEEN operator to NOT BETWEEN. This is similar in concept, except working toward exclusion, instead of inclusion. So, if we want to check if a given value is outside of a range, we can use the NOT BETWEEN operator as below.

value NOT BETWEEN low AND high;

Again, similarly to the double WHERE statements, NOT BETWEEN simplifies the burden into a single statement. For sanity, we’ll skip the SELECT WHERE example.

## Using BETWEEN in pgAdmin / PostgreSQL

Below, we’ve taken the BETWEEN statement for a road test on our address table.

WHERE address_id BETWEEN 10 AND 20;

How sweet was that? Syonara, comparison operators. Conversely, if we convert the above query into a NOT BETWEEN operator, we should see the below statement return the following results.

WHERE address_id NOT BETWEEN 10 AND 20;

Okay, that was cool. Let’s hold up for a quick second. What about non-integer columns, such as data? Caveat: there’s a lot more to data types than our humble example below. For the purposes of this article, we can take a YYYY-MM-DD date and place the values into strings.

SELECT rental_id,rental_date,inventory_id FROM rental

WHERE rental_date BETWEEN ‘2005-05-24’ AND ‘2005-05-27’;

Voila!

## Wrap-Up

Alright, for those of you reading this later, it’s 2 a.m. on a Friday night / Saturday morning, and I’m about ready to call it a night. Sorry I’m not providing a better conclusion for you today. I’m excited to delve further into more complex SQL queries. Keep track of my shared journey of a beginner learning SQL. Cheers!

## ORDER BY Clause: SQL Statement Fundamentals

Welcome back to our SQL learning journey! It’s been a week and a half since my last post on using LIMIT. Work got crazy and I got the flu! 🙁 But we’re back in action. Today, we’ll delving deeper into SQL statements in PostgreSQL: ORDER BY.

Let’s jump in. Why would you need a statement that orders data? Whenever you query data from a table, PostgreSQL will by default return the rows in the order they were inserted into the table. (Read: not the order you want.)

To sort the result set from your SQL query, you can use the ORDER BY clause in the SELECT statement and specify a certain ascending or descending order.

# Sample ORDER BY Clause Syntax

Here’s an example of the ORDER BY clause would look like within a SELECT statement.

SELECT column_1, column_2

FROM table_name

ORDER BY column_1 ASC / DESC;

Some important notes for the ORDER BY clause:

• Specify the column you want to sort by with the ORDER BY clause
• If you sort the results by multiple columns, use a comma to separate between the two columns
• Use ASC to sort the results in ascending order
• Use DESC to sort the results in descending order
• Should you leave the ORDER BY clause blank, it will use ASC (ascending) by default

## ORDER BY Clause Examples in SQL Statements

Alright, first up. We’ll do a basic SELECT statement, adding both ORDER BY and LIMIT clauses. Code and screen shot below. The query should select the first and last name columns from the customer table, ordered by last name ascending (A > Z), returning only the first 10 rows.

SELECT first_name,last_name  FROM customer

ORDER BY last_name ASC

LIMIT 10;

Let’s try another example. What if we want to do an advanced / multiple sort? Let’s try it out, and change it up ever so slightly from the first sample query.

SELECT first_name,last_name

FROM customer

ORDER BY first_name ASC,

last_name DESC;

If we scroll down to the first set of duplicate first names, we’ll see the last name has been presented in descending order (Z > A).

## More Details About the ORDER BY Clause

Did you know? In PostgreSQL, you can ORDER BY columns that aren’t explicitly selected within the SELECT statement? E.g. We could only select first and last name, but order by their address_id value. Interesting, yes? Important caveat, other SQL programs, such as MySQL, may not let you do this.

Below:

SELECT first_name FROM customer

ORDER BY last_name ASC;

## Wrap-Up

Thanks for joining me and hopefully you’ve learned the essentials for the ORDER BY clause. Feel free to check out the entire journey on how to learn SQL, thanks!