str_replace challenge

[thessoro]

hi!
i need this to work:

$string="hi %i am% just an %example%";

i need the first "%" to be replaced by "<b>", the second by "</b>", the third by "<b>" again.

i mean alternate substitution.

i tried str_replace ("%",array ('<b>','</b>'),$string); but it doesn't work (in fact it shouldn't).

Any ideas? thanks in advance. (i hope that my little english is enough for you to understand me)

[laserlight]

not sure if an alternative using regular expressions would be better, but you could try:

$str_array = explode('%', $string);
$fragments = count($str_array);
$string = '';
for ($i = 0; $i < $fragments; $i++) {
	if ($i % 2 == 0) {
		$string .= str_replace('%', '<b>', $str_array[$i]);
	}
	else {
		$string .= str_replace('%', '</b>', $str_array[$i]);
	}
}

[thessoro]

regular expressions frightens me... 🙂 so i think that is a better solution. Thanks.

[laserlight]

my apologies, very serious error there, was just about to sleep when I thought of it :eek:

Maybe try this instead:

$str_array = explode('%', $string);
$fragments = count($str_array);
$string = $str_array[0];
for ($i = 1; $i < $fragments; $i++) {
    if ($i % 2 == 1) {
        $string .= '<b>' . $str_array[$i];
    }
    else {
        $string .= '</b>' . $str_array[$i];
    }
}

[EricC]

Originally posted by thessoro
Any ideas? thanks in advance. (i hope that my little english is enough for you to understand me)

I'm still learning regular expressions myself, so I can appreciate your hesitance to use them, however they can be very powerful when approached in small doses.. 😉

$string="hi %i am% just an %example%";

$after = preg_replace("/\\%(.*?)\\%/", "<b>\\\\1</b>", $string);

print "Before $string <br>";
print "After $after <br>";

The PHP manual has a section that discusses pattern matching and its a good read (albeit a bit intimidating at first) with a lot of samples to help clairify things.

Good luck.