python - modify a list of strings via regex

Question

I have a list of strings

query_var = ["VENUE_CITY_NAME == 'Bangalore' & EVENT_GENRE == 'ROMANCE' & count_EVENT_GENRE >= 1","VENUE_CITY_NAME == 'Jamshedpur' & EVENT_GENRE == 'HORROR' & count_EVENT_GENRE >= 1"]
len(query_var)   #o/p 2

I want to modify this list to get

 query_var = ["df['VENUE_CITY_NAME'] == 'Bangalore' & df['EVENT_GENRE'] == 'ROMANCE' & df['count_EVENT_GENRE'] >= 1","df['VENUE_CITY_NAME'] == 'Jamshedpur' & df['EVENT_GENRE'] == 'HORROR' & df['count_EVENT_GENRE'] >= 1"]

This is my attempt:

for res in query_var:
    res = [x for x in re.split('[&)]',res)]
    print(res)
    res =  [x.strip() for x in res]
    print(res)
    res = [d.replace(d.split(' ', 1)[0], "df['"+d.split(' ', 1)[0]+"']") for d in res]
    print(res)

which produces the output:

 ["VENUE_CITY_NAME == 'Bangalore' ", " EVENT_GENRE == 'ROMANCE' ", ' count_EVENT_GENRE >= 1']
 ["VENUE_CITY_NAME == 'Bangalore'", "EVENT_GENRE == 'ROMANCE'", 'count_EVENT_GENRE >= 1']
 ["df['VENUE_CITY_NAME'] == 'Bangalore'", "df['EVENT_GENRE'] == 'ROMANCE'", "df['count_EVENT_GENRE'] >= 1"]
 ["VENUE_CITY_NAME == 'Jamshedpur' ", " EVENT_GENRE == 'HORROR' ", ' count_EVENT_GENRE >= 1']
 ["VENUE_CITY_NAME == 'Jamshedpur'", "EVENT_GENRE == 'HORROR'", 'count_EVENT_GENRE >= 1']
 ["df['VENUE_CITY_NAME'] == 'Jamshedpur'", "df['EVENT_GENRE'] == 'HORROR'", "df['count_EVENT_GENRE'] >= 1"]

AS expected, but when I print query_var it was not changed

query_var
Out[47]: 
   ["VENUE_CITY_NAME == 'Bangalore' & EVENT_GENRE == 'ROMANCE' & count_EVENT_GENRE >= 1","VENUE_CITY_NAME == 'Jamshedpur' & EVENT_GENRE == 'HORROR' & count_EVENT_GENRE >= 1"]

As you can see my code does not produce the desired output. Is there a better way, for example with a list comprehension?

You need to assign res value to query_var in order to change it. — Sameer Mirji
– Sameer Mirji, Commented Jan 27, 2016 at 12:37

timgeb · Accepted Answer · 2016-01-27 16:23:58Z

3

Heres a regex/list comprehension solution:

>>> [re.sub('(\w+)\s*(==|>=)', r"df['\1'] \2", s) for s in query_var]
["df['VENUE_CITY_NAME'] == 'Bangalore' & df['EVENT_GENRE'] == 'ROMANCE' & df['count_EVENT_GENRE'] >= 1", "df['VENUE_CITY_NAME'] == 'Jamshedpur' & df['EVENT_GENRE'] == 'HORROR' & df['count_EVENT_GENRE'] >= 1"]

Adjust it as needed for more general data, i.e. permitting '<=', for example.

edit in response to the comment:

[re.sub('(\w+)(\s*(==|>=).*?)(\s*&|$)', r"(df['\1']\2)\4", s) for s in query_var]

edited Jan 27, 2016 at 16:23

answered Jan 27, 2016 at 12:39

timgeb

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3 Comments

Satya Over a year ago

@timgeb-just one more small help....i want to include () for each segment sep by & symbol...ex.["(df['VENUE_CITY_NAME'] == 'Bangalore') & (df['EVENT_GENRE'] == 'ROMANCE') & (df['count_EVENT_GENRE'] >= 1)"

Satya Over a year ago

as for this i can't raise one more question.i can do this after running the reg exp.but i am just not getting how to do that inside the reg exp as suggested by you...

timgeb Over a year ago

@Satya updated, please provide the correct/full specifications in the original question next time

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