I have a number of strings similar to
Current Level: 13.4 db.
If your float is always expressed in decimal notation something like
>>> import re >>> re.findall("\d+\.\d+", "Current Level: 13.4 db.") ['13.4']
A more robust version would be:
>>> re.findall(r"[-+]?\d*\.\d+|\d+", "Current Level: -13.2 db or 14.2 or 3") ['-13.2', '14.2', '3']
If you want to validate user input, you could alternatively also check for a float by stepping to it directly:
user_input = "Current Level: 1e100 db" for token in user_input.split(): try: # if this succeeds, you have your (first) float print float(token), "is a float" except ValueError: print token, "is something else" # => Would print ... # # Current is something else # Level: is something else # 1e+100 is a float # db is something else