regex - python regular expression $[a-zA-Z ][0-9a-zA-Z ]* with forbidding -

i looking regular expression in python, in string finds me:

$[a-za-z_][0-9a-za-z_]* 

there can more of , can seperated whitespaces (\s)

this quite easy, need forbid whole string if there did not match pattern. (+ empty string ok)

i'll give examples:

$x$y0123 => ok, gives me [$x, $y0123] $ => bad (only $) "" or "  \t" => ok, gives me []     $x      @hi => bad, cause @hi, not match pattern 

it can more regular expressions, doesn't have one.

regex = re.compile("(\$[a-za-z_][0-9a-za-z_]*)") regex.findall(string)

this ok, if don't have check things also.

hmm, i'm not entirely sure you're trying do, maybe need 2 regex: first check validity of format, , second retrieve matches.

import re stuff = ["$x$y0123", "$", "", "  \t", "$x      @hi"]  p1 = re.compile(r'(?:\$[a-z_]\w*|\s)*$', re.ignorecase) p2 = re.compile(r'\$[a-z_]\w*|\s+', re.ignorecase)  thing in stuff:     if p1.match(thing):         print(p2.findall(thing)) 

will print:

['$x', '$y0123'] [] ['  \t'] 

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