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Kotlin Programming: The Big Nerd Ranch Guide, First Edition
book

Kotlin Programming: The Big Nerd Ranch Guide, First Edition

by Josh Skeen, David Greenhalgh
July 2018
Intermediate to advanced content levelIntermediate to advanced
400 pages
12h 14m
English
Big Nerd Ranch Guides
Content preview from Kotlin Programming: The Big Nerd Ranch Guide, First Edition

Null Safety

Because Kotlin distinguishes between nullable and non-nullable types, the compiler is aware of the possibly dangerous situation of asking a variable defined as a nullable type to do something when the variable might not exist. To shield against these dangers, Kotlin will prevent you from calling functions on a value defined as nullable until you have accepted responsibility for this unsafe situation.

To see what this looks like in practice, try to call a function on beverage. This is a fancy tavern, and, as such, all drink names should be capitalized. Try to call capitalize on beverage. (You will see more String functions in Chapter 7.)

Listing 6.5  Using a nullable variable (Tavern.kt)

fun main(args: Array<String>) ...
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Publisher Resources

ISBN: 9780135165188