CODEWITHSUNDEEP
pythonstringpandas
I. crespo
I. crespo

Reputation: 63

if one of several strings are in other string: return a value + matching string, Python

I would like to ask your help with an "if statement" inside a function that I am using to aggregate some data in a dataframe. With this function I wanted to check if any of several strings are in other string in one column of my dataframe to return an specific value and the matching string.

This is what I have so far and it does what I need. For example, if "f" and "k" are in my string ("fk"), once I apply my function on this row (find_string("fk")), my function will return "success". Additionally I would also like to have the string that was found in the list, in this case 'f'. Something like "success" + "f"

 def find_string(b):
     if "a"  in b or "c"  in b or "d"  in b or "f"  in b:
         return "success"  ## here I want to get the matching string

Any suggestion?

I am using python 2.7.13 with pandas library.

Upvotes: 1

Views: 46

Answers (3)

Elazar
Elazar

Reputation: 21595

def find_string(b):
   for c in ['a', 'c', 'd', 'f']:
       if c in b:
           return 'success ' + c
   return 'failure'

>>> find_string('fk')
'success f'

Upvotes: 1

Eric Duminil
Eric Duminil

Reputation: 54223

You could simply use set intersections. It doesn't require any if or loops and should be very efficient:

>>> set('try to find a substring') & set('acdf')
{'a', 'f', 'd'}
>>> set('no substring') & set('acdf')
set()

If you really want to use pandas, look at @Coldspeed's solution.

Upvotes: 1

cs95
cs95

Reputation: 402423

If you're using pandas, use str.extract + np.where, it's much faster.

v = df['yourCol'].str.extract('([acdf])', expand=False)
df['newCol'] = np.where(v.isnull(), '', 'success' + v.astype(str))

Upvotes: 2

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