Instead of wondering what regex I need for each time I need a regex, I like to learn how to do basic string replacement with regexes.
How do you take one string and replace it with another with regexes in PHP ?
For example how do you take all '/' and replace them with '%' ?
If you just want to do basic string replacement (i.e. replace all 'abc' with '123') then you can use str_replace, which doesn't require using regex. For basic replacements, this will be easier to set up and should run faster.
If you want to use this as a tool to learn regex though (or need more complicated replacements) then preg_replace is the function you need.
You should look into preg_replace. For your question
$string = "some/with/lots/of/slashes";
$new_string = preg_replace("/\//","%",$string);
echo $new_string;
/ as the delimiter, you don't have to escape it inside the expression.I like to learn how to do basic string replacement with regexes.
That's a little broad for this forum. However, to answer a more specific question like:
For example how do you take all '/' and replace them with '%' ?
You could do that like this:
$result = preg_replace('#\/#', '%', 'Here/is/a/test/string.');
Here is a Rubular that proves the regex.
Note, you are not limited to using the common / delimiter, which means when working with forward slashes it is often easier to change to a different delimiter EG.
$mystring = 'this/is/random';
$result = preg_replace('#/#', '%', $mystring);
This will make '#' the delimiter, rather than the standard '/', so it means you do not need to escape the slash.
I would do this simply with strtr which is very suitable for character mapping, e.g.
strtr('My string has / slashes /', '/', '%');
If you want to also replace the letter a with a dash:
strtr('My string has / slashes /', '/a', '%-');
As you can see, the second and third argument define the transformation map.
strtrandstr_replacewhere applicable. Regular expressions are great but not always necessary.