Haxe Code Cookbook
Haxe programming cookbookBeginnerUsing strings

Using strings

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Defining string literals take be done by wrapping text inside double or single quotes:

"string text";
'string text';

Assigning strings to variables:

var a:String = "a"; // with type declaration
var b = "b"; // without type declaration

Combine two strings:

var greeting = "hello";
var message = greeting + " world"; 
trace(message); // output: hello world

String interpolation / Template literals

In Haxe string literals can also be template literals using so-called string interpolation. This only works when you use single quotes.

var name = "Mark";
var age = 33;
var message = 'Hello, I am $name and my age is $age';
trace(message); // output: Hello, I am Mark and my age is 33

Note that this is basically the same as writing: var message = "Hello, I am " + name + " and my age is " + age

In simple cases you can use $myvariable, for more complex expressions you can use ${myvariable}.

var age = 33;
var year = 2017;
var message = 'I am born in ${year - age}';
trace(message); // output: I am born in 1984

String operations

It is possible to use multiple operators on a string:

// add two strings
trace("apple" + "pear"); // applepear

// compare if both are the same
trace("apple" == "pear"); // false
trace("apple" == "apple"); // true

// compare if both are different
trace("strawberry" != "blueberry"); // true
trace("patato" != "patato"); // false

It is also possible to compare strings with other operators:

trace("ABCB" > "ABBBB"); // true
trace("ABCB" < "AAAA"); // false

So, "ABCB" is greater than "ABBBB". This works like this because strings are compared lexicographically. Lexical order (according Wikipedia) is a generalization of the way the alphabetical order of words is based on the alphabetical order of their component letters.

This can be useful when you for example want so sort a list of strings:

// Creating an array with strings
var fruits:Array<String> = ["apple", "pear", "banana"];
fruits.sort(function(a, b) return a > b ? 1 : -1);
trace(fruits); // output: apple,banana,pear

Note that this can also be confusing when there are numbers in the text: e.g. "11.5" > "3" will result to false. This is because "1" comes earlier in the alphabet than "3". If you expect it to work those strings as actual numbers, you need to convert them to numbers first:

var a = "11.5";
var b = "3";
trace(a > b); // false
trace(Std.parseFloat(a) > Std.parseInt(b)); // true because compared as actual numbers

Multiline strings

Long literal strings in Haxe can be written easily. String are multi-line:

var fruits = "
- apple
- pear
- banana";

String manipulation

String has various methods for manipulating text. These method does not change the original string, but return a new one instead. See the String API documentation for all string methods.

trace("Haxe is great!".toUpperCase()); // HAXE IS GREAT!
trace("Haxe is great!".toLowerCase()); // haxe is great!

Reverse a string:

function reverse(a:String):String {
  var arr = a.split('');
  return arr.join('');

trace(reverse("Haxe is great!")); // !taerg si exaH

For more string methods, StringTools in the Haxe Standard Library provides a lot more methods for Strings. Here are a few examples:

trace(StringTools.replace("Haxe is great!", "great", "fun")); // Haxe is fun!
trace(StringTools.startsWith("Haxe is great!", "Haxe")); // true
trace(StringTools.endsWith("Haxe is great!", "Haxe")); // false
trace("#" + StringTools.hex(255, 6)); // #0000FF

StringTools is ideally used with using StringTools and then acts as an extension to the String class, this would allow to do:

trace("Haxe is great!".replace("great", "fun")); // Haxe is fun!
trace("Haxe is great!".startsWith("Haxe")); // true
trace("Haxe is great!".endsWith("Haxe")); // false

Single string character code

Use .code on a constant single character to compile its ASCII character code:

trace("\n".code); // output: 10
trace("@".code); // // output: 64

If you need to do this with a runtime string character, you can use StringTools.fastCodeAt.

API documentation


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Category:  Beginner