[SOLVED] What does this mean?

[AV1611]

I have this statement in a script:

 

$value += $data[$i];

 

what does += mean?

Thanks

 

[Lodius2000]

http://www.w3schools.com/PHP/php_operators.asp

 

+=  example: x += y is the same as x = x+y

 

therefore if $value has no value or is 0, then $value = $data, but if $value has a value, then it becomes the sum of itself and $data

[AV1611]

http://www.w3schools.com/PHP/php_operators.asp

 

+=  example: x += y is the same as x = x+y

 

therefore if $value has no value or is 0, then $value = $data, but if $value has a value, then it becomes the sum of itself and $data

I looked for hours in the php online manual, but I didn't know what it was called so didn't know how to find it.

 

I had a GD script that was failing and that line was giving a Notice: but I didn't know why.

 

Thanks.