PHP preg_replace：替换字符串中出现在最后一个带空格的连字符之前的所有连字符

Question

Using preg_replace (or other PHP-based option): I need to replace all hyphens in a string, that appear before the last hyphen , with space.

Example #1 of the Result I Need:

string = My-Cool-String - 201

result = My Cool String - 201

Example #2 of the Result I Need:

Note: Notice that this string example only contains 1 hyphen.

string = My Cool String - 201

result = My Cool String - 201

My current code is stripping out ALL hyphens and replacing with space.

$origString = 'My-Cool-String - 201';
$newString = preg_replace("/[^A-Za-z0-9]/", ' ', $origString);

Additional Context:

In the example string of My Cool String - 201

My Cool String represents the name of a resort.

201 represents the room number.

I was running into my originally stated issue when the name of the resort contained hyphens.

Answer 1

You may use

preg_replace('/-(?=.* -)/', ' ', $origString)

See the PHP demo and the regex demo . To account for any whitespace use '/-(?=.*\\s-)/' , or '/-(?=.*\\s-\\s)/' (if there should be whitespaces on both sides of the hyphen).

Details

• - - a hyphen
• (?=.* -) - a positive lookahead that requires - after any 0+ chars other than line break chars, as many as possible (use s flag after / to match across line breaks).