very weird loop

Gasolene

this loop, loops 4ever, it 'never' executes the "print" line (not even once) it just hangs

note: this line works fine exept when $keywords[0] = "select"
that's the weird part.

$keywords is an array of strings
and $keywords[0] equils "select"

for( $i = 0; $keywords[$i]; $i++ )
{
print "hi";
}

why????

weekender

the second argument in a for loop has to be a comparison - ie <, >, =, !=, >=, <=

consider the line

for( $i = 0; $i<10; $i++ )

what you are saying is "start with $i = 0, and add 1 to $i each loop until $i is less than 10"

in your statment

for( $i = 0; $keywords[$i]; $i++ )

you are saying "start with $i = 0, and add 1 to $i until SELECT". There is no comparison, and even if there was, you cannot compare a number to 'select'.

adam

Gasolene

NOPE, the second part of the loop is a condition, when the condition fails, the loop ends.

here is how a for loop works...

for( executed once ; this is your condition (if this fails, loop ends); this part executes after every loop )

ex: for( print "once" ; true; print "hi" ) {}
this would output: oncehihihihihihi
and continue 4ever

if u have a compasason (i$ < 10); when $i becomes bigger than 10, that returns false;

so in my loop, the loop ends when $keywords[$i]; is false (a.k.a. end of array)

think of it like this. (this is the equivilent of the for loop)

$i = 0;
while ( $keyword[$i] == true )
{
$i++;
}

Gasolene

sorry,

seems that my problem has nothing to do with the loop, just bad debugging.

Shrike

$keywords[$i] is a shorthand condition, PHP does the work for you by checking the existence of $keywords[$i]. Your loop however doesn't provide something to fail on. In earlier versions of PHP I think this would have worked, but more recent versions don't let you perform calculations against undefined variables/indexes, or at least throws a warning.

<?php
$keywords = array('one', 'two', 'three');
for( $i = 0; $keywords[$i]; $i++ ) 
{ 
print $keywords[$i]; 
} 
?>

produces

onetwothree
Notice: Undefined offset: 3

i.e. an error, the loop exits because of this not because it has finished counting. This is more appropriate

<?php
$keywords = array('one', 'two', 'three');
for( $i = 0; array_key_exists($i, $keywords); $i++ ) 
{ 
print $keywords[$i]; 
} 
?>