method

In his excellent book, Beginning Scala, David Pollak provides a series of statements that can be considered as a recipe for avoiding the use of null values in your Scala code. I've organized his statements here in the following three sections.

1) General rules about null and Option

We begin with the following general rules regarding the use of null values in Scala code:

UPDATE: This example shows how to create an implicit method in Scala 2.9 or older. You can use a slightly simpler approach with Scala 2.10 and newer, which I've documented in this Scala 2.10 implicit class example.

I'm not going to do much writing here today, but instead I'll just demonstrate how an implicit method argument works with implicit fields in Scala. Without any further ado, here's some code:

The Scala List class filter method implicitly loops over the List you supply, tests each element of the List with the function you supply. Your function must return true or false, and filter returns the list elements where your function returns true.

(Note: Even though I use a List in these examples, the filter method can be used on any Scala sequence, including Array, List, Vector, Seq, etc.)

Android FAQ: Can you share some source code for an Android send email method?

If you need a simple Android 'send email' function/method, this source code should do the trick for you:

Java FAQ: How do I square a number in Java?

You can square a number in Java in at least two different ways:

1. Multiply the number by itself.
2. Call the Math.pow function.

Here's how to square a number by multiplying it by itself:

i = 2
int square = i * i

In that case, if you print the value of square, it will be 4.

Here's how you call the Math.pow method to square a number: