PHP: Convert Integer Variable to String Variable

Sooner or later, a newbie in PHP programming comes to the question of how to convert, transform or rewrite a variable specified as a specific type to another type.

Especially if someone is coming from other programming languages in which it is not possible to simply attach a number type to a string type, this question is reasonable in PHP. This is why I came to the idea of writing this small tutorial.

Automatic Type Conversion

In terms of types, PHP is a very liberal. For example, if you would like to output a number as text, it is sufficient to pass the variable containing the number:

echo $zahl;

In this case, PHP is doing the type conversion automatically. Also many functions like substr(), for example, are also accepting numbers as parameter which are then processed as string. Therefore, in most cases, you do not have to care about types in PHP.

Explicit Type Conversion

If you nevertheless would like to do a type casting in PHP explicitly, you can proceed in this way, for instance:

$text = $zahl . '';
$text = (string) $zahl;
$zahl = (int) $text;

It is sufficient to attach an empty string to a number - and the number becomes a string. Alternatively, you can also write the type in brackets in front of the variable to implement the type transformation. For example, the following keywords are allowed for this:

• (int) and (integer) for type casting to an integer number
• (float), (double) and (real) for type casting to a float number
• (string) for the transformation of the variable to a string
• (bool) or (boolean) for the type conversion to boolean

Others are (array), (object) or (unset) for a cast to null. But I think, you will need them very seldom.