alvin alexander

scala cookbook

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By Alvin Alexander. Last updated: August 1 2017

As I finish editing this book in January, 2014, it’s a busy time. In addition to releasing this book, I just finished writing a 700+ page computer programming book for O’Reilly named Scala Cookbook.

A funny thing about the Scala Cookbook: I wrote it on a whim, as a dare, wondering, “Am I good enough to write this book, on my own?” I doubted myself for a little while, but then overcame my fears and sent an email to the people at O’Reilly. As I’ve said throughout this book, all you are is attitude.

How to split strings in Scala

By Alvin Alexander. Last updated: July 9 2017

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 1.3, “How to Split Strings in Scala.”

Problem

You want to split a string into parts based on a field separator, such as a string you get from a CSV or pipe-delimited file.

Solution

Use one of the split methods that are available on String objects:

How to create multiline strings in Scala

By Alvin Alexander. Last updated: July 9 2017

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 1.2, “How to Create Multiline Strings in Scala.”

Problem

You want to create multiline strings within your Scala source code, like you can with the “heredoc” syntax of other languages.

Solution

In Scala you create multiline strings by surrounding your text with three double quotes:

How to test String equality in Scala alvin July 9, 2017 - 5:50pm

This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 1.1, “Testing String Equality in Scala.”

Problem

When using Scala, you want to compare two strings to see if they’re equal, i.e., whether they contain the exact same sequence of characters.

Solution

In Scala you compare two String instances with the == operator. Given these strings:

How I came to write the Scala Cookbook

By Alvin Alexander. Last updated: June 22 2017

The funny thing about writing the Scala Cookbook is that it started as a whim. I was just about to leave for a vacation at the beach, and right before I turned off the computer, a thought flashed in my mind, “I should contact the people at O’Reilly about writing a cookbook for Scala.” I then had a doubt that they would actually do it, but I applied the “What the heck” rule — i.e., “What the heck, what do I have to lose?” — and sent the email.

I dug around the internet for a few minutes, found the correct O’Reilly email address, sent them a message, turned off the computer, and drove to the beach. While I was at the beach the publisher wrote and said, “Love it, send me a full proposal!”

So if you’re thinking about doing something, but are afraid or uncertain about doing it ... apply the “What the heck” rule, and give it a shot. :)

Writing a book is an adventure. To begin with it is a toy and an amusement.

By Alvin Alexander. Last updated: May 2 2017

“Writing a book is an adventure. To begin with it is a toy and an amusement. Then it becomes a mistress, then it becomes a master, then it becomes a tyrant. The last phase is that just as you are about to be reconciled to your servitude, you kill the monster and fling him to the public.”

~ Winston Churchill

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A Java tuple class (Tuple2 or Pair, if you prefer)

By Alvin Alexander. Last updated: March 28 2017

After working with Scala for a long time, I had to come back to Java for a while to work on an Android app. Right away I missed a lot of things from the Scala world, including all of the built-in Scala collection methods, and other things as simple as the Scala Tuple classes.

If you haven’t used them before, a Scala Tuple class lets you write code like this:

Tuple<String, Integer> t = new Tuple<>("age", 41);

If you’re comfortable with generics, the Java implementation of a Tuple class like this is simple:

Good God, what happened to this apartment?

By Alvin Alexander. Last updated: November 3 2016

I now enter the next phase of my Scala Cookbook project, known as, “Good God, what happened to this apartment while I was writing that book?!”

(A Facebook post from November 3, 2012.)

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