php preg_match'/'与正则表达式

Question

I'm matching routes, so If I have a string

"/teacher/jkDfl"

and I want to check if it starts with

"/teacher/"

My newbie approach is hoping this evaluates to true

preg_match("/^/teacher//", "/teacher/jkDfl")

But I think the issue is all the '/' characters, and looking around nothing popped out at me. I probably need to work on my google-fu, but I figure this is simple for someone with xp in regex.

Cheers!

Answer 1

Delimiters are somewhat arbitrary, so, the often used # delimiter would work:

preg_match("#^/teacher/#",....

If you're very fond of / 's, you can escape them with \\ 's:

preg_match("/^\/teacher\//",....

... or let PHP do that for you (good for user provided literal strings):

preg_match("/^".preg_quote("/teacher/","/")."/",...

Answer 2

You can use # as regexp delimiter.

preg_match("#^/teacher/#", "/teacher/jkDfl")

You could also capture the various parameters (eg jkDfl) with regexps, see:

http://php.net/manual/en/function.preg-match.php

In this case:

if (preg_match("#^/teacher/([^?]*)#", $url, $gregs))
{
    $teacher = $gregs[1]; // "jkDfl"
    ....
}

Answer 3

You have two options: change the delimiter or escape the literals.

Different delimiter:

preg_match("%^/teacher/%", "/teacher/jkDfl");

Escape literals:

preg_match("/^\/teacher\//", "/teacher/jkDfl");
//or
preg_match("/^" . preg_quote("/teacher/", "/") . "/", "/teacher/jkDfl");

Answer 4

它应该是

preg_match("/^\/teacher\//", "/teacher/jkDfl")