Pandas fuzzy merge/match name column, with duplicates

Question

I have two dataframes currently, one for donors and one for fundraisers. I\'m trying to find if any fundraisers also gave donations, a

Answer 1

Here's a bit more pythonic (in my view), working (on your example) code, without explicit loops:

def get_donors(row):
    d = donors.apply(lambda x: fuzz.ratio(x['name'], row['name']) * 2 if row['Email'] == x['Email'] else 1, axis=1)
    d = d[d >= 75]
    if len(d) == 0:
        v = ['']*3
    else:
        v = donors.ix[d.idxmax(), ['name','Email','Date']].values
    return pd.Series(v, index=['donor name', 'donor email', 'donor date'])

pd.concat((fundraisers, fundraisers.apply(get_donors, axis=1)), axis=1)

Output:

                 Date           Email        name donor name     donor email           donor date
0 2013-03-27 10:00:00          a@a.ca    John Doe   John Doe          a@a.ca  2013-03-01 10:39:00
1 2013-03-01 10:39:00          a@a.ca    John Doe   John Doe          a@a.ca  2013-03-01 10:39:00
2 2013-03-02 10:39:00          d@d.ca  Kathy test   Kat test          d@d.ca  2013-03-27 10:39:00
3 2013-03-03 10:39:00    asdf@asdf.ca   Tes Ester                                                
4 2013-03-04 10:39:00  something@a.ca    Jane Doe   Jane Doe  something@a.ca  2013-03-04 10:39:00

Answer 2

I would use Jaro-Winkler, because it is one of the most performant and accurate approximate string matching algorithms currently available [Cohen, et al.], [Winkler].

This is how I would do it with Jaro-Winkler from the jellyfish package:

def get_closest_match(x, list_strings):

  best_match = None
  highest_jw = 0

  for current_string in list_strings:
    current_score = jellyfish.jaro_winkler(x, current_string)

    if(current_score > highest_jw):
      highest_jw = current_score
      best_match = current_string

  return best_match

df1 = pandas.DataFrame([[1],[2],[3],[4],[5]], index=['one','two','three','four','five'], columns=['number'])
df2 = pandas.DataFrame([['a'],['b'],['c'],['d'],['e']], index=['one','too','three','fours','five'], columns=['letter'])

df2.index = df2.index.map(lambda x: get_closest_match(x, df1.index))

df1.join(df2)

Output:

    number  letter
one     1   a
two     2   b
three   3   c
four    4   d
five    5   e

Update: Use jaro_winkler from the Levenshtein module for improved performance.

from jellyfish import jaro_winkler as jf_jw
from Levenshtein import jaro_winkler as lv_jw

%timeit jf_jw("appel", "apple")
>> 339 ns ± 1.04 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

%timeit lv_jw("appel", "apple")
>> 193 ns ± 0.675 ns per loop (mean ± std. dev. of 7 runs, 1000000 loops each)

Answer 3

How to identify Fuzzy duplication in DataFrame using Pandas

This my data frame

def get_ratio(row):
name = row['Name_1']
return fuzz.token_sort_ratio(name,"Ceylon Hotels Corporation")
df[df.apply(get_ratio, axis=1) > 70]