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, and if so, copy some of that information into my fundraiser dataset (donor name, email and their first donation). Problems with my data are:

1. I need to match by name and email, but a user might have slightly different names (ex 'Kat' and 'Kathy').
2. Duplicate names for donors and fundraisers:
   • 2a) With donors I can get unique name/email combinations since I just care about the first donation date
   • 2b) With fundraisers though I need to keep both rows and not lose data like the date.

Sample code I have right now:

import pandas as pd
import datetime
from fuzzywuzzy import fuzz
import difflib 

donors = pd.DataFrame({"name": pd.Series(["John Doe","John Doe","Tom Smith","Jane Doe","Jane Doe","Kat test"]), "Email": pd.Series(['a@a.ca','a@a.ca','b@b.ca','c@c.ca','something@a.ca','d@d.ca']),"Date": (["27/03/2013  10:00:00 AM","1/03/2013  10:39:00 AM","2/03/2013  10:39:00 AM","3/03/2013  10:39:00 AM","4/03/2013  10:39:00 AM","27/03/2013  10:39:00 AM"])})
fundraisers = pd.DataFrame({"name": pd.Series(["John Doe","John Doe","Kathy test","Tes Ester", "Jane Doe"]),"Email": pd.Series(['a@a.ca','a@a.ca','d@d.ca','asdf@asdf.ca','something@a.ca']),"Date": pd.Series(["2/03/2013  10:39:00 AM","27/03/2013  11:39:00 AM","3/03/2013  10:39:00 AM","4/03/2013  10:40:00 AM","27/03/2013  10:39:00 AM"])})

donors["Date"] = pd.to_datetime(donors["Date"], dayfirst=True)
fundraisers["Date"] = pd.to_datetime(donors["Date"], dayfirst=True)

donors["code"] = donors.apply(lambda row: str(row['name'])+' '+str(row['Email']), axis=1)
idx = donors.groupby('code')["Date"].transform(min) == donors['Date']
donors = donors[idx].reset_index().drop('index',1)

So this leaves me with the first donation by each donor (assuming anyone with the exact same name and email is the same person).

Ideally I want my fundraisers dataset to look like:

Date                Email       name        Donor Name  Donor Email Donor Date
2013-03-27 10:00:00     a@a.ca      John Doe    John Doe    a@a.ca      2013-03-27 10:00:00 
2013-01-03 10:39:00     a@a.ca      John Doe    John Doe    a@a.ca      2013-03-27 10:00:00 
2013-02-03 10:39:00     d@d.ca      Kathy test  Kat test    d@d.ca      2013-03-27 10:39:00 
2013-03-03 10:39:00     asdf@asdf.ca    Tes Ester   
2013-04-03 10:39:00     something@a.ca  Jane Doe    Jane Doe    something@a.ca  2013-04-03 10:39:00

• I tried following this thread: is it possible to do fuzzy match merge with python pandas? but keep getting index out of range errors (guessing it doesn't like the duplicated names in fundraisers) :( So any ideas how I can match/merge these datasets?

• doing it with for loops (which works but is super slow and I feel there has to be a better way)

Code:

fundraisers["donor name"] = ""
fundraisers["donor email"] = ""
fundraisers["donor date"] = ""
for donindex in range(len(donors.index)):
    max = 75
    for funindex in range(len(fundraisers.index)):
        aname = donors["name"][donindex]
        comp = fundraisers["name"][funindex]
        ratio = fuzz.ratio(aname, comp)
        if ratio > max:
            if (donors["Email"][donindex] == fundraisers["Email"][funindex]):
                ratio *= 2
            max = ratio
            fundraisers["donor name"][funindex] = aname
            fundraisers["donor email"][funindex] = donors["Email"][donindex]
            fundraisers["donor date"][funindex] = donors["Date"][donindex]

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]