how od i echo the first 50 chars in a string containing 5000

thewomb

hey there, what im looking to do is echo the first 50 chars in a string containing 500+

i can evaluate the string length

<? 

$len = strlen( $var ) ; 
echo 'lengh ='.$len;

length = 5000

?>

but how do i echo the first 50 or 100 chars only?

thanx in advance

tasistro

$maxprint=50;
for ($c=0;$c<$maxprint;$c++) { echo $string[$c]; }
?>

Weedpacket

Originally posted by tasistro
<?

$maxprint=50;
for ($c=0;$c<$maxprint;$c++) { echo $string[$c]; }
?>

😃😃😃

coreyp_1

echo substr ($var, 0, 50);

Where:
$var = string variable
0 = starting character (i.e., first character)
50 = # of characters to include

specs here: http://us3.php.net/substr

tasistro

echo substr ($var, 0, 50);

here memory usage could be an issue if the string is really big.

Weedpacket

Originally posted by tasistro
>> echo substr ($var, 0, 50);

here memory usage could be an issue if the string is really big.

Why? $var is already in memory (and you call 500 bytes big?) Certainly I didn't see any appreciable rise when I substr()ed a nine-megabyte-long file (a convenient mail archive). I guess substr() just reads the existing string and takes what it needs instead of copying the entire string and then cutting off the bits it doesn't. You have to admit, the former sounds like a more sensible implementation of that function.

tasistro

As far as I understand and correct me if I'm wrong, your not passing it by reference which probably means it gets copied into a new memory space.

Sure 9 megs sound fine and runs ok. Now setup a site and have 100 concurrent connections and see how stressed your OS becomes trying to deliver that much memory.

Will have to check the code to see exactly what substr does.

Weedpacket

Originally posted by tasistro
As far as I understand and correct me if I'm wrong, your not passing it by reference which probably means it gets copied into a new memory space.

PHP's memory management is described here (although it's not so important, since substr() is an internal function and implemented in C, not PHP).

In the real world I wouldn't even consider reading an entire 9MB file just for the sake of the first fifty characters. I just did that because I needed a big string as an example that wouldn't need too much string processing to generate. Since I was going to be the only user and I was only going to use it once or twice, I didn't care if it wouldn't tolerate 100 hits/sec.