python - Regex to include alphanumeric and _ -

python - Regex to include alphanumeric and _ -

i'm trying create regular look match alphanumeric characters , underscore _. regex: "\w_*[^-$\s\]" , impression regex means alphanumeric character \w, underscore _, , no -,$, or whitespace. correct?

regular expressions read patterns match characters in string, left right, pattern matches alphanumeric, underscore (0 or more), @ to the lowest degree 1 character not hyphen, dollar, or whitespace.

since you're trying alternate on character types, utilize character class show characters you're allowing:

[\w_]

this checks part of string matches it, let's anchor origin , and of string:

^[\w_]$

and see character class lacks quantifier, matching on 1 character. can prepare using + (if want 1 or more characters, no empty strings) or * (if want allow empty strings). i'll utilize + here.

^[\w_]+$

as turns out, \w character class includes underscore, can remove redundant underscore pattern:

^[\w]+$

and have 1 character in character class, no longer need character class brackets @ all:

^\w+$

and that's need, unless i'm missing requirements.

python regex