how do you parse out a text value in php - php

Question

I have a line like this:
$line1= "System configuration: lcpu=96 mem=393216MB ent=16.00"
I need to parse out lcpu, mem and ent values from this string. I have tried something like this:
$lcpu=preg_match('/(?P<lcpu>\w+)= (?P<digit>\d+)/', $line1, $matches);
does not seem to be getting the lcpu values from the string $line1, any ideas what I am doing wrong here?

Answer 1

You've nearly got a query string there, so maybe
$string = explode(": ", $line1);
$string = str_replace(" ", "&", $string[1]);
parse_str($string, $values);
echo $values['lcpu'];

Answer 2

One other way to pares strings:
$line1= "System configuration: lcpu=96 mem=393216MB ent=16.00";
list($lcpu, $mem, $ent) = sscanf($line1, "System configuration: lcpu=%d mem=%dMB ent=%f");

Answer 3

Why not use a simple function to get the string between two strings. If the lcpu value is always going to be prefixed by "lcpu=" and end with a " " (space) then you could use:
function getBetween($str, $start, $end)
{
$r = explode($start, $str);
if (isset($r[1]))
{
$r = explode($end, $r[1]);
return $r[0];
}
return false;
}
and just say:
if (getBetween($line1, 'lcpu=', ' ')) { ... }
It'll return false if nothing is found.

Answer 4

Personally, I would parse by syntax instead (rather than searching for specific keys):
<?php
$input = "System configuration: lcpu=96 mem=393216MB ent=16.00";
// Strip out "System configuration: "
$values = preg_replace('~^.*?:\s*$~', '', $input);
// Split on whitespace separator
$values = preg_split('~\s+~', $values);
// Convert to associative array
foreach ($values as $i => $item)
{
// Explode on assignment (=)
list($k, $v) = explode('=', $item);
$values[$k] = $v;
unset($values[$i]);
}

Answer 5

There are many ways to parse a string. Explode is usually faster than using a regex, so this way may be more performant than the methods which rely on regular expressions.
list( , , $lcpu_pair )= explode( " ", $line1 );
list( , $lcpu_value ) = explode( "=", $lcpu_pair );
$lcpu_value will contain '96'.