PHP Data Types

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PHP Data Types : Booleans

Description

Booleans are 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 :

  1. $height=100;  

  2. $width=50;  

  3. if ($width == 0)  

  4. {  

  5. echo "The width needs to be a non-zero number";  

  6. }  

  7. ?>  

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 :

  1. $height=100;  

  2. $width=50;  

  3. if ($width)   

  4. {   

  5. echo "The area of the rectangle is".$height*$width;   

  6. }  

  7. else   

  8. {   

  9. echo "The width needs to be a non-zero number";  

  10. }  

  11. ?>  

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 values 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