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pythonregexpep

Less repeating yourself for re.sub with lists


I need to apply some regex substitutions on every element on a list. I wrote a function to repeat myself less. anyway there's still too much repeating. How could I optimize this?

def cleanlist(mylist, regex, substitution):
    tmp_list = mylist
    cleaned_list = [re.sub(regex, substitution, line) for line in tmp_list]
    return cleaned_list


create_table_parts = cleanlist(create_table_parts, "(SET).+?(\n)", "\n") 
create_table_parts = cleanlist(create_table_parts, "(__|\(__).*?\n|(^\)|(?<=\n)(\n))", "")
create_table_parts = cleanlist(create_table_parts, "\"", "")
create_table_parts = cleanlist(create_table_parts, "(?<=CREATE\sTABLE\s).+?(\.)", "") 
create_table_parts = cleanlist(create_table_parts, "(PRIMARY\sKEY\s).+?(\n)|(FOREIGN\sKEY\s).+?(\n)|", "")
create_table_parts = cleanlist(create_table_parts, "(CREATE_INDEX\s).+?(\n)", "") 

Solution

  • Put your patterns in a list and loop:

    patterns = [
        ("(SET).+?(\n)", "\n"),
        ("(__|\(__).*?\n|(^\)|(?<=\n)(\n))", ""),
        ("\"", ""), ("(?<=CREATE\sTABLE\s).+?(\.)", ""),
        ("(PRIMARY\sKEY\s).+?(\n)|(FOREIGN\sKEY\s).+?(\n)|", ""),
        ("(CREATE_INDEX\s).+?(\n)", "")
    ]
    
    for patt, sub in patterns:
        create_table_parts = cleanlist(create_table_parts, patt, sub)
    

    You could even use reduce() for this, instead of the for loop:

    create_table_parts = reduce(lambda ctp, patt: cleanlist(ctp, *patt),
                                patterns, create_table_parts)
    

    but it's a personal call wether or not that's any more readable.