This codelab discusses how to work with multiple values in your code, and introduces a variety of data structures, including arrays, lists, sets, and maps. The ability to effectively use collections enables you to implement common features of Android apps, such as scrolling lists, as well as solve a variety of real-life programming problems that involve arbitrary amounts of data. A collection might be an ordered list, a grouping of unique values, or a mapping of values of one data type to values of another. To build apps involving arbitrary amounts of data, you need to learn how to use collections.Ĭollection types (sometimes called data structures) let you store multiple values, typically of the same data type, in an organized way.

However, in the code you've written so far, you've mostly worked with data consisting of a single value, like a number or piece of text displayed on the screen. In many apps, you've probably seen data displayed as a list: contacts, settings, search results, etc.

For loop with index kotlin