match once

[glenelkins]

hi

 

i maybe have a string like "hellohellobyehello"

 

i want to match for "hello" so use:

 

preg_match ( '%hello%', $string );

 

but how would i return true if the string contains only 1 occurance of "hello". so in this example it would be false because there are 3 "hello" in there

[Garethp]

preg_match_all("~hello~", $String, $Temp);

if(sizeof($Temp[0]) != 1)

{

//fail

}

[glenelkins]

ok all well and good but the string and pattern will have more than just in my example to macth.

 

it may have a string like: '1234hellobyedonttalktome'

 

pattern may be '%1234hello%';

 

only want to make sure the string has 1 occurance of the "hello" but must start with 1234

[cags]

If you need to match multiple things you might have wanted to mention that initially. With regular expressions, theres no point in saying I want to match this, getting a pattern then saying oh it must also match this... the chances are the pattern will be changed completely. It's important to know from the outset exactly what needs to be matched. Having said that, in your particular example you're probably better off using multiple patterns. Also using the information provided so far your probably (IMHO) better off using str functions rather than regex.

 

if(substr($input, 0, 4) == '1234' && substr_count($input, 'hello') == 1) {

[Garethp]

preg_match_all("~hello~", $String, $Temp);

if(preg_match("^1234", $String) && sizeof($Temp[0]) != 1)

[cags]

preg_match_all("~hello~", $String, $Temp);

if(preg_match("^1234", $String) && sizeof($Temp[0]) != 1)

 

Whilst that would also work (assuming you remembered the delimeters on the preg_match call) it would be slower.

[thebadbad]

FYI, preg_match_all() returns the number of full pattern matches.