I have the following three strings:
>>> s_no = '¥2,571'
>>> s_yes = '$2,57'
>>> s_yes = '2,57 $'
How would I construct a regex to match only the second one? The one I am using so far is:
re.search(r'\,\d{2}[\s|$]?',s) # should start on a comma. Unconcerned what comes before it.
Basically I want it to allow a (1) comma -- (2) then two digits -- (3) then either the end of the string or a space.
Given:
>>> tgt="""\
... >>> s_no = '¥2,571
... >>> s_yes = '$2,57
... >>> s_yes = '2,57 $"""
You can use the pattern ,\d\d(?: |$)
Python:
>>> re.findall(r',\d\d(?: |$)', tgt, flags=re.M)
[',57', ',57 ']
re.M flag in the above?
re.M is for the multiline flag so that the ^ and $ regex meta characters match the beginning of logical lines versus only at the beginning and end of a string. It is only required in the example here because tgt is three logical lines and $ would only match at the very end of the string without it.You've pretty much got most of it, but you want to make sure that you don't use a character set []. Instead, use a capture group (). If you want to get either the end of the string, or a space and then the end of the string, you want (\s$|$). Putting it together: r'\,\d{2}(\s$|$)'
There are plenty of websites (like regexr.com) where you can put in any regex, and it automatically highlights the text. It usually helps me out in the rare case I use regexes.
dollar_sign = r"\$"
dollars = r"(?P<dollars>\d+)"
cents = r"(?:,(?P<cents>\d{2}))?"
amount_re = r"^" + dollar_sign + dollars + cents + r"\s*$"
m = re.search(amount_re, "$2,57 ")
print("Got", m.group('dollars'), "dollars", end='')
print(m.group('cents') if m.group('cents') is not None else "even")
