Can you beat my code?

Anon

There are two arrays having sttings. I need to get all the strings from the first array, which have got any string from the array 2, in whole or in part within them.

E.g.
Array $combi
cater
bater
sater

Array $words
cat
mat
bat
lat
tat
hat

so, i should get from array 1
cater (becuase it has the word \'cat\')
bater (becuase it has \'bat\')

to accomplish this, i wrote the following simple piece of code..and it works. The problem is that my second array - $words is BIG, with atleast 30000 elements or words. So this piece of code takes a lot of time, and usually times out.

What is a better and faster way to do this?

$c=count($combi)-1;
$w=count($words)-1;

for ($i=0;$i<=$c;$i++) {
for ($j=0;$j<=$w;$j++) {
if (eregi (trim($words[$j]),trim($combi[$i]))) {
echo \">>\".$combi[$i].\" \".$words[$j].\"<br>\";
}
}
}

Thanks.
Saurabh Kumar

toma42

$j, $i, $w, $c
These variable names are poorly named.

Try using a foreach loop as
foreach ($smalllist as $word) {
foreach ($biglist as $checkword) {
}
}

Also, where is the array coming from? If it's a file, grep would work faster. If it's some other source you could use shared memory to keep the array around so you don't need to reload it on every request.

brandonschnell

eregi() functions can be slow. if you're not using regular expressions, use one of the other string functions like strpos.

Anon

The bigger array is coming from a file. How do I use grep in PHP? I store the array in session after the first time. Is this OK?

toma42

if using unix:

results = grep regex file.txt;

If you want to store the session in shared memory try preg_grep after retrieving the array.

I think storing the file in the session is extremly stupid. It causes every page request, whether the file is used or not, to process the array again.

Anon

but the array will be processed again, IF I continue the session by session_start() on that page..isn't it?
And I will only continue the session if I need that array.

Also...the preg_grep function will help me to 'Return array entries that match the pattern'.....the manual dopes not say anything about it dealing with shared memory space...kindly enlighten me on this point.