for loop

Java enum examples/tutorial

Java enum FAQ: Can you share some Java enum examples, such as how to declare a Java enum, and how to use a Java enum in a for loop, if then statement, and Java switch statement?

As described in Sun's Java documentation, a Java enum "is a type whose fields consist of a fixed set of constants ... you should use enum types any time you need to represent a fixed set of constants." Let's take a look at some Java enum examples to see how this works.

By Alvin Alexander on April 16, 2013

Scala for loop syntax examples (including yield and guards)

Scala FAQ: Can you share some examples of the Scala for loop syntax?

Sure. I'm going to start with a comparison to Java for loops, because that's what I was just thinking about.

In Java you might write a for loop like this:

for (int i = 0; i < 10; i++) {
  System.out.println(i);
}

The equivalent for loop in Scala looks like this:

for (i <- 1 to 10) {
  println(i)
}

(The use of parentheses isn't necessary in either example, but most for loops will be longer.)

By Alvin Alexander on May 17, 2013

The Scala for loop translation scheme

If you're interested in the details of the translation scheme of a Scala for loop (for comprehension), here's a quick look at how a for loop is translated into, well, other code.

A simple Scala for loop

In a first example, we'll start with the following Scala class:

class Main {
  def foo { for(i <- 0 to 10) println(i) }
}

Next, I compile this class from the command line like this:

By Alvin Alexander on March 26, 2013

Scala - Using a for loop with embedded if statements

If you ever need to use a Scala for loop (for comprehension) with one or more embedded if statements, I hope the following example is helpful:

By Alvin Alexander on May 7, 2013

Scala for/yield examples (for loop and yield examples)

I just found some notes from when I first began working with Scala, and I was working with the yield keyword in for loops. If you haven't worked with something like yield before, it will be helpful to know how it works. Here's a statement of how the yield keyword works in for loops, based on the documentation in the book, Programming in Scala:

By Alvin Alexander on April 22, 2013

Java String array examples (with Java 5 for loop syntax)

Java String array FAQ: Can you share some Java array examples, specifically some String array examples, as well as the Java 5 for loop syntax?

Sure. In this tutorial, we'll show how to declare, populate, and iterate through a Java String array, including the Java 5 for loop syntax. Because creating a String array is just like creating and using any other Java object array, these examples can also work as more generic object array examples.

By Alvin Alexander on April 22, 2013

Iterating over Scala Lists with foreach and for

Scala List/foreach FAQ: How do I iterate over a Scala List using the foreach method and for loop?

There are a number of ways to iterate over a Scala List using the foreach operator and for comprehension, and I'll show a few of those approaches here.

By Alvin Alexander on April 16, 2013

The AppleScript for loop (and while loop) examples

AppleScript for loop FAQ: How do I use an AppleScript for loop? (Also, how do you use an AppleScript while loop?)

This is actually a bit of a trick question, as there is no AppleScript for loop or while loop syntax. Instead you use the AppleScript repeat command, as shown in the following examples.

AppleScript for loop examples

Where you might expect an AppleScript for loop to iterate over a list, you use the AppleScript "repeat with" syntax:

By Alvin Alexander on January 31, 2011

PHP array - How to loop through a PHP array

PHP array FAQ: How do I iterate (loop) through a PHP array?

Answer: The easiest way to loop through a PHP array is to use the PHP foreach operator. If you have a simple one-dimensional array, like the $argv array which lets you access command line arguments, you can loop through it like this:

By Alvin Alexander on September 5, 2010

Shell script counter FAQ - How to increment a counter in a shell script

Unix/Linux shell script FAQ: Can you share a simple Linux shell script that shows how to count, i.e., a shell script that increments a counter in a for loop or while loop?

Sure, I just needed to increment a while loop counter myself, so I thought I'd share my example shell script code here.

By Alvin Alexander on May 3, 2013
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