Better way to parse input from string in Python?

Question

I'm making a bot that will output different information depending on the user input (a string). I'm wondering if there is a better way to parse the input and redirect to different outcomes:

def query(msg: str):
    if re.compile(r"moci(o|ó)?n(es)? de (procedimiento)s?", re.IGNORECASE).search(msg):
        return open("mociones/mocion_procedimiento.txt", "r").read()

    elif re.compile(r"moci(o|ó)?n(es)? de (ó|o)?rden(es)?", re.IGNORECASE).search(msg):
        return open("mociones/mocion_orden.txt", "r").read()

    elif re.compile(r"moci(o|ó)?n(es)? de duda(s)?", re.IGNORECASE).search(msg):
        return open("mociones/mocion_duda.txt", "r").read()

    elif re.compile(r"moci(o|ó)?n(es)? de privilegio(s)?", re.IGNORECASE).search(msg):
        return open("mociones/mocion_privilegio.txt", "r").read()

    ...

    elif re.compile(r"defender (el|los)? anteproyectos?", re.IGNORECASE).search(msg):
        return open("debate_particular/index.txt", "r").read()

    elif re.compile(r"anteproyectos?", re.IGNORECASE).search(msg):
        return open("anteproyecto/index.txt", "r").read()

    else:
        return "_*ERROR*_\n\nNo search results were found for \n`{query}`".format(query=msg)

"Better" how? If this is working code you think could be improved, look into Code Review. Also, note that by explicitly re-compiling the regexes every time you call the function it's probably less efficient, if anything, than not compiling them at all; to benefit from the compilation, move it outside the function. — jonrsharpe
– jonrsharpe, Commented Jan 29, 2017 at 14:25

georg · Accepted Answer · 2017-01-29 17:58:36Z

2

An obvious suggestion would be to have a dict regex => path and use a loop instead of a bunch of if statements:

paths = {
    r"(?i)moci[oó]?n(es)? de (procedimiento)s?": "mociones/mocion_procedimiento.txt",
    r"(?i)moci[oó]?n(es)? de [óo]?rden(es)?": "mociones/mocion_orden.txt"
}

def path_for_msg(msg):
    for r, p in paths.items():
        if re.search(r, msg):
            return p

Also re.compile is hardly if ever needed, because re takes care of compiling behind the scenes.

If the order is important, then the proper data structure is a list of tuples:

paths = [
    (r"(?i)moci[oó]?n(es)? de (procedimiento)s?", "mociones/mocion_procedimiento.txt"),
    (r"(?i)moci[oó]?n(es)? de [óo]?rden(es)?", "mociones/mocion_orden.txt")
}

def path_for_msg(msg):
    for r, p in paths:
        if re.search(r, msg):
            return p

edited Jan 29, 2017 at 17:58

answered Jan 29, 2017 at 14:33

georg

216k57 gold badges324 silver badges401 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

margobra8 Over a year ago

But is there a way I can mantain the order? This seems to be ignoring it at all... Order is important

Community · Accepted Answer · 2017-05-23 11:45:32Z

0

An alternative is to adopt a more object-oriented approach, creating separate classes to handle different types of inputs and arranging them into a chain of responsibility - similar to georg's suggestion except you'd be iterating over message handler objects instead of raw regex patterns.

See this answer for more details.

edited May 23, 2017 at 11:45

CommunityBot

11 silver badge

answered Jan 29, 2017 at 14:45

Tagc

9,1409 gold badges68 silver badges118 bronze badges

Collectives™ on Stack Overflow

Better way to parse input from string in Python?

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related