Regex/translate clear solution for Currency Style by martin_b - python coding challenges

Enable Javascript in your browser and then refresh this page, for a much enhanced experience.

Regex/translate solution in Clear category for Currency Style by martin_b

def checkio(t):
    # regex:
    # match string starting with $, followed by 1-3 digits,
    # followed by 0 or more times dot and 3digits,
    # followed by 0 or once by comma and 2 digits,
    # which are not followed by a digit
    import re
    return re.sub("\$(\d{1,3})(\.\d{3})*(,\d{2}(?!\d))?",
                  lambda s: s.group(0).translate(t.maketrans(',.', '.,')), t)

April 11, 2016

Comments:

CalebA.Kelley on Jan. 31, 2019, 8:05 p.m.
I think that I understand the regular expression matching pattern. But I don't understand how you have used a lambda. From my understanding, the re.sub takes a matching pattern, a function accepts a match object(here you created a lambda to swap the values of '.' and ',' on match group zero), t is the target string that the regular expression is run against. Is that correct. I really need to start using more regex. This is a pretty elegant solution, compared to mine.

martin_b on Feb. 2, 2019, 5:45 p.m.
Yes, regex is very powerful tool. I could have used <pre class='brush: python'>"".maketrans(',.', '.,') </pre> instead of a bit confusing <pre class='brush: python'>t.maketrans(',.', '.,') </pre> as just any string is needed to create the translations table.

sawako.oono on June 27, 2021, 2:05 p.m.
When the number of digits after the decimal point is 1 it does not work. (Such as "$5,1")\ It should be like this to include those cases. <pre class='brush: python'>"\$(\d{1,3})(\.\d{3})*(,\d{1,2}(?!\d))?" </pre>

Strings Theory

0 %

PyCharm The Python IDE for Professional Developers. Enjoy productive Python, web and scientific development with PyCharm. Download it now!