PHP Data Types : Booleans
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Description
Booleans is the easiest type. It can be either TRUE or FALSE. It is used in control structure like the testing portion of an if statement.
Consider the following example :
<?php
$height=100;
$width=50;
if ($width == 0)
{
echo "The width needs to be a non-zero number";
}
?>
In the above code the result of the equal-than operator is a Boolean. In this case, it would be false and, therefore, the echo statement will never execute.
Now consider the next example :
<?php $height=100;
$width=50;
if $width { echo "The area of the rectangle is
$height*$width; }
else { echo "The width needs to be a non-zero number"; }
?>
In this example no comparison operator is used. But PHP automatically converted $width value 50 to its Boolean equivalent true and calculate the area of the rectangle i.e. execute the commands inside the if() statement.
List of the types of Boolean value equivalents
| Data Type | True Value | False value |
|---|---|---|
| Integer | All non-zero values | 0 |
| Floating point | All non-zero values | 0.0 |
| Strings | All other strings | Empty strings ()"" The zero string ()"0" |
| Null | Never | Always |
| Array | If it contains at least one element |
If it does not contain any elements |
| Object | Always | Never |
| Resource | Always | Never |
