Concatenating strings

Concatenation of strings means taking two strings and joining them sequentially into one. For example, you can use the+` operator to concatenate two strings:

var str1:String = "green";
var str2:String = "ish";
var str3:String = str1 + str2; // str3 == "greenish"

You can also use the += operator to the produce the same result, as the following example shows:

var str:String = "green";
str += "ish"; // str == "greenish"

Additionally, the String class includes a concat() method, which can be used as follows:

var str1:String = "Bonjour";
var str2:String = "from";
var str3:String = "Paris";
var str4:String = str1.concat(" ", str2, " ", str3);
// str4 == "Bonjour from Paris"

If you use the + operator (or the += operator) with a String object and an object that is not a string, ActionScript automatically converts the nonstring object to a String object in order to evaluate the expression, as shown in this example:

var str:String = "Area = ";
var area:Number = Math.PI * Math.pow(3, 2);
str = str + area; // str == "Area = 28.274333882308138"

However, you can use parentheses for grouping to provide context for the + operator, as the following example shows:

trace("Total: $" + 4.55 + 1.45); // output: Total: $4.551.45
trace("Total: $" + (4.55 + 1.45)); // output: Total: $6