I'm trying to understand dash character
- needs to escape using backslash in regex?
var url = '/user/1234-username'; var pattern = /\/(\d+)\-/; var match = pattern.exec(url); var id = match; // 1234
As you see in the above regex, I'm trying to extract the number of id from the url. Also I escaped
- character in my regex using backslash
\. But when I remove that backslash, still all fine ....! In other word, both of these are fine:
Now I want to know, which one is correct (standard)? Do I need to escape dash character in regex?
You only need to escape the dash character if it could otherwise be interpreted as a range indicator (which can be the case inside a character class).
/-/ # matches "-" /[a-z]/ # matches any letter in the range between ASCII a and ASCII z /[a\-z]/ # matches "a", "-" or "z" /[a-]/ # matches "a" or "-" /[-z]/ # matches "-" or "z"
- has a meaning only inside a character class
, so when you're outside of it you don't need to escape
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