NEWB loop through text

[salewit]

I know this is probably very simple, but I can't figure it out. I've tried it with a WHILE and a DO loop, and can't get it to work.

$string = "This is a test. This is only a test. Testing 123";
$position = strpos($string,"test");
if ($position !== false) {
// processes
// more processing
}

How do I keep this loop going until I've gone through the string? I know this is incredibly simple, but I'm stuck.

 

[jpadie]

$string = "This is a test. This is only a test. Testing 123";
$position = 0
while ($position = strpos($string,"test", $position) !== FALSE):
// processes
// more processing
endwhile;

 

[jpadie]

oops - don't forget the semicolon after the

$position = 0; //semicolon

 

[salewit]

Thanks for the response. I tried this and it resulted in an endless loop.

$position = 0
while ($position = strpos($string,"test", $position) !== FALSE):

Doesn't using the variable $position twice in this statement throw off the loop? Maybe it should be something like:

$start_position = 0
while ($position = strpos($string,"test", $start_position) !== FALSE):
$start_position = $position;

I don't know... I haven't tried it yet.

Also, this threw me off on the bracketing. I've never seen a loop started with a colon and ending with a semi-colon and not the curly brackets. I didn't get an error, so it must be right. Just never saw that.

Sam

PS Hmmm I just tried my alteration, and it didn't work either. Endless loop. Stuck again.

 

[sleipnir214]

Also, this threw me off on the bracketing. I've never seen a loop started with a colon and ending with a semi-colon and not the curly brackets. I didn't get an error, so it must be right. Just never saw that.

It's an alternate syntax. I recommend strongly against its use because, as you can see, it can cause readability issues. But it's in the manual:

http://www.php.net/manual/en/control-structures.alternative-syntax.php

Are you looking for a loop that runs through a string a character at a time? How 'bout:

<?php
$the_string = 'This is a test. This is only a test. Testing 123';

for ($counter = 0; $counter < strlen($the_string); $counter++)
{
   print $the_string{$counter};
   print "\r\n";
}
?>

Want the best answers? Ask the best questions! TANSTAAFL!

 

[salewit]

Actually, I found a routine that does what I want. I don't know HOW it does it, but it works.

What I was trying to do was to look for instances of any kind of link (

http://)

in my text string and add the tags to make it clickable. It got ridiculously complex and the routine I found used eregi_replace which basically did it all on one line. It's gonna be quite awhile before I can begin to understand how that one works.

Thanks for the help.
Sam

 

[jpadie]

NEWB

sorry - basic mistake forgetting to increment the position counter. here is a revised script (with some built in loop prevention).

Sleipnir214 is right that the colon is part of the alternative syntax. quite opposite to sleipnir, however, i have been using it for the last while because i believe it enormously enhances readability and reduces the chance of syntax errors (particularly for nested loops and conditionals).

$string = "This is a test. This is only a test. Testing 123";
$position = -1;
$cnt = 0;
$len = strlen($string);
$increment = 1; // this will be ok but you may find it better to increment by the length of the needle
$needle = "test";
while (($position = strpos($string, $needle, $position + $increment)) !== FALSE):
// processes
// more processing
	echo "position is $position <br/>";
	if ($cnt > $len ):
		break;
	else:
		$cnt ++;
	endif;
endwhile;