To use | or || in an if statement

[timtrust123]

Hi

I'm a little confused as to the useage of either | or ||

should I use....

if ($ftp_file_size < $lower_size | $ftp_file_size > $upper_size )

or should i use

if ($ftp_file_size < $lower_size || $ftp_file_size > $upper_size )

Whats the difference beteween the two?

HELP appreciated

 

[waiterm]

'|' is a bitwise OR operator so works differently with numbers than it does to strings.

'||' is a logical OR operator which evaluates from the left to right of a string or number matching as it goes.

SO basically you should use '|' to compare integers and '||' to compare strings, although '||' will compare integers as well as strings, whereas '|' won't compare strings!!

Rob Waite

http://www.hostpipe.co.uk?src=TT

 

[ishnid]

The basic rule of thumb is to use || unless there's a reason you need to perform bitwise operations on numbers.

When used in the context of your example (i.e. simply evaluating for truth), | happens to have a similar effect to || when used on numbers but it's not really what it's designed for.