Python regex alphanumeric without underscore

I've been trying to match with regex all alphanumeric characters, except for the underscore. I'm currently using r"^[a-zA-Z0-9]*", but I wondered if it was possible to use \w and exclude _.

Thanks!

asked May 22, 2014 at 21:38

Yes, like that: [^\W_]

Where \W is the opposite of \w

answered May 22, 2014 at 21:40

I'm trying to understand why my regex keeps picking up the underscore when I only want it to return alphanumeric characters as denoted by the '\w'. When I remove the underscores in the string, the output is 'm', which is what I thought it would be even with the underscores included. I know I can write it differently to make sure it does not include the underscores, but why is it including them? See example below.

import re

string = '__comMand__aNnd__conqQuer__'
match = re.search[r'[\w]\1', string, re.IGNORECASE]
print[match.group[1] if match else -1]

# output: m

Regex alphanumeric without underscore

This answer provides the context of a full regexp. If you wanted the leading 'alphas' to be two or three digits followed by alpha-numeric, just add the appropriate quantifier: $string =~ m/\A\p{alpha}{2,3}[\p{alpha}\p{Number}]*\z/.

Java regex to allow only alphanumeric characters. We can use the given regular expression used to validate user input in such a way that it allows only alphanumeric characters. Alphanumeric characters are all alphabets and numbers i.e. letters A–Z, a–z, and digits 0–9. 1.

Java regex to allow only alphanumeric characters We can use the given regular expression used to validate user input in such a way that it allows only alphanumeric characters. Alphanumeric characters are all alphabets and numbers i.e. letters A–Z, a–z, and digits 0–9 . Alphanumeric characters with space, Alphanumeric regex pattern. With alphanumeric regex at our disposal, the solution is dead simple.

Python has a special sequence \w for matching alphanumeric and underscore. Please note that this regex will return true in case if string has alphanumeric and underscore. For example: This regex will return true for java2blog_. That’s all about Python Regex to alphanumeric characters.

Regex to match any alphanumeric string

Java2blog is a alphanumeric string Java$2_blog is not a alphanumeric string Here, we need to import re module and use re.matches [] method to check alphanumeric characters. You can use another regex for checking alphanumeric characters and underscore.

Regular Expression Validator: Allow Alphanumeric Characters and , TryParse. regex match alphanumeric only string. Alphabets [Upper and Lower case] and Numbers [Digits] and Space as valid characters. Alphabets [Upper and Lower case] and Numbers [Digits] and Space as valid characters.

If you're using JavaScript, which doesn't have a "dotall" option, try [\s\S]*. This means "match any number of characters that are either whitespace or non-whitespace" - effectively "match any string". Another option that only works for JavaScript [and is not recognized by any other regex flavor] is [^]* which also matches any string.

Expression. ^ [ [\d {5}-\d {4}]| [\d {5}]| [ [A-Z]\d [A-Z]\s\d [A-Z]\d]]$. Description. This expression matches three different formats of postal codes: 5 digit US ZIP code, 5 digit US ZIP code + 4, and 6 digit alphanumeric Canadian Postal Code. The first one must be 5 numeric digits. The ZIP+4 must be 5 numeric digits, a hyphen, and then 4 numeric digits.

Searching with Regular Expressions [RegEx] A regular expression is a form of advanced searching that looks for specific patterns, as opposed to certain terms and phrases. With RegEx you can use pattern matching to search for particular strings of characters rather than constructing multiple, literal search queries.

Grep alphanumeric underscore

Using an asterisk with the file extension rather than the file name will instruct the grep. Using the above example for error messages, looking through all log files might look like this: grep -c 'one\|two\|three' /var/log/*.log Searching Recursively For Multiple Matches. Using grep will only search within the current directory with the asterisk in use.

Non-ASCII characters start at 0x80 and go to 0xFF when looking at bytes. Grep [and family] don't do Unicode processing to merge multi-byte characters into a single entity for regex matching as you seem to want. The -P option in my grep allows the use of \xdd escapes in character classes to accomplish what you want.

Alphanumeric Characters: Since computers [or central processing units, to be specific] use machine language in the form of numbers to communicate, computer programmers need to write their instructions using numbers rather than alphabet characters. To do this, programmers use numeric representations of what humans see as alphabet characters.

Regex for letters and underscore

[a-zA-Z0-9]+ One or more letters or numbers. The extension must be at least one character long and must contain only letters and numbers. This is typical, but if you wanted allow underscores, that could be addressed as well. You could also supply a length range {2,3} instead of the one or more + matcher, if that were more appropriate.

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With some variations depending on the engine, regex usually defines a word character as a letter, digit or underscore. A word boundary \b detects a position where one side is such a character, and the other is not.

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