![]() In this case we want a delimiter that’s a little more concrete, so “one or more” spaces. It can be used with other regex expressions in different ways. The \s is used to express a single space, whitespace, tab, carriage return, new line vertical tab, and form feed characters in Regex. The space or whitespace can be also expressed in regex. The reason I used a instead of a ‘*’ is because a plus is defined as one or more of the preceding element, where an asterisk is zero or more. Different characters are expressed with different regex signs. I also preserved the capture group around the whitespace, if you don’t want this then remove the brackets as already described above. If you want to match multiple whitespaces then see my comments above. Note as I have already pointed out that the negative lookahead ?! will not match when wordB is followed by a single whitespace and wordc. I replaced wordc with swordc since that is more explicit. The only difference is that not the regex matches whitespace OR. Preserving your original regex you can use: (1) A whitespace ( s ) in a regular expression matches any one of the characters: space, formfeed ( f ), newline ( n ), return ( r ), tab ( t ). Hello the problem is not the expression but the HTML out put that are not considered as whitespace. Are you capturing the whitespace to a group for a reason? If not you could just remove the brackets, i.e. (s*) – the brackets indicate a capturing group. You may want to consider if you want at least one space. * will match 0 or more spaces so it will match wordAwordB. The method matches () takes two arguments: the first is the regular expression, and the second is the string we want to match. Of course, if you do want to match lines with wordc after wordB then you shouldn’t use a negative lookahead. If you want to match against more than one space before wordc you can use (?!s*wordc) for 0 or more spaces or (?!s* wordc) for 1 or more spaces depending on what your intention is. You may want to be more precise and use (?!swordc). Currently you are relying on the space after ?! to match the whitespace. You don't have to wrap a single entity in a group to repeat it, and I have added a second zero-or-more-spaces at the end which is what you are missing to make it work. (?! wordc) is a negative lookahead, so you wont match lines wordA wordB wordc which is assume is intended (and is why the last line is not matched). Note that all matches are replaced no matter how many spaces. Here are some example matches and the associated replacement output: Note the single space between ?! and wordc which means that wordA wordB wordc will not match, but wordA wordB wordc will. ![]() Furthermore, you can find the Troubleshooting Login Issues section which can answer your unresolved problems and equip you with a lot of relevant information. This means match wordA followed by 0 or more spaces followed by wordB, but do not match if followed by wordc. Regex Whitespace Characters LoginAsk is here to help you access Regex Whitespace Characters quickly and handle each specific case you encounter. Assuming that it is doing what you want it to. Print(len(re.Your regex should work ‘as-is’. So if you like to count how many times _, / or spaces occurs in the strings than you can use: import re You can count not only for a single character but also for a list or a pattern. The advantage of the regex is the customization. Of course Python offers faster solution in case of just counting: unt('_') ![]() So let's count number of _ in the next URLS: import re Example 1: Match space or no space in a stringĪnd you would like to match followed by zero or one space than you can use regex syntax: ].*)", text))Įxample 3: Match strings with no more than n occurrencesįinally if you like to find all strings which contain n number of spaces( or any other character) then you can use the next regex: re.findall(r"()", text). ![]() Let's demonstrate usage of them with an example. If so, you may use the following syntax to match similar patterns: Need to use a regex to match - "no character or one character" or "zero or one space".
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