Rules on use of == double equals (see p142, 146)

ababb · January 20th, 2005, 09:01 AM

Do you know the rationale for the use of double equals sign? Is it PHP syntax that requires it?

In what situations is it required?

ABabb
Dallas TX

Snib · January 20th, 2005, 05:58 PM

The double equals signs are to test for equality between two variables and/or values. A single equals sign is used for assignment.

Code:

//"set variable1 to 'value'"
$variable1 = "value";

//"if variable1 is 'value' do something()"
if($variable1 == 'value')
{
  something();
}

//this is probably not what you want to do:
//"if variable1 is successfully set to 'value' do something()"
if($variable1 = 'value')
{
  something();
}

//and this will cause an error - think of it as a sentence fragment
$variable1 == 'value';

hth,

-Snib - http://www.snibworks.com
Where will you be in 100 years?