How to return multiple keys in a string if a given string matches the keys value in a dictionary

Question

I'm trying to iterate through a dataframe column to extract a certain set of words. I'm mapping these as key value pairs in a dictionary and have with some help managed to set on key per row so far.

Now, what I would like to do is return multiple keys in the same row if the values are present in the string and these should be separated by a | (pipe).

Code:

import pandas as pd
import numpy as np

df = pd.DataFrame({'Name': ['Red and Blue Lace Midi Dress', 'Long Armed Sweater Azure and Ruby',
                            'High Top Ruby Sneakers', 'Tight Indigo Jeans',
                            'T-Shirt Navy and Rose']})

colour = {'red': ('red', 'rose', 'ruby'), 'blue': ('azure', 'indigo', 'navy')}

def fetchColours(x):
    for key, values in colour.items():
        for value in values:
            if value in x.lower():
                return key
    else:
        return np.nan

df['Colour'] = df['Name'].apply(fetchColours)

Output:

        Name                            Colour
0       Red and Blue Lace Midi Dress    red
1  Long Armed Sweater Azure and Ruby    blue
2    High Top Ruby Sneakers             red
3        Tight Indigo Jeans             blue
4              T-Shirt Navy and Rose    blue

Expected result:

        Name                                 Colour
0       Red and Blue Lace Midi Dress         red
1       Long Armed Sweater Azure and Ruby    blue|red
2       High Top Ruby Sneakers               red
3       Tight Indigo Jeans                   blue
4       T-Shirt Navy and Rose                blue|red

Nathan · Accepted Answer · 2018-04-01 13:52:02Z

2

The problem is that you return directly after finding a key, while you should continue searching untill all results are found:

def fetchColours(x):
    keys = []
    for key, values in colour.items():
        for value in values:
            if value in x.lower():
                keys.append(key)
    if len(keys) != 0:
        return '|'.join(keys)
    else:
        return np.nan

For this to work you have to change:

 colour = {'red': ('red', 'rose', 'ruby'), 'blue': ('azure', 'indigo', 'navy')}

to

 colour = {'red': ('red', 'rose', 'ruby'), 'blue': ('azure', 'blue','indigo', 'navy')}

Because otherwise it won't search for the term 'blue' in each sentence, meaning it cannot add this key to the list in the first example.

edited Apr 1, 2018 at 13:52

answered Apr 1, 2018 at 13:39

Nathan

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6 Comments

Rehan Azher Over a year ago

This code should work but somehow it is not, first row should be red|blue but it is only setting red.

Bob Harris Over a year ago

I tried this solution and got the same result as @RehanAzher unfortunately.

Rehan Azher Over a year ago

@BobHarris yes and I am unable to find the reason why :)

Nathan Over a year ago

The problem is that 'blue' is not one of the values of key 'blue'

Rehan Azher Over a year ago

@Nathan your solution is correct, actually i had it ready but was trying to find the reason why my output can not match OP expected output.

|

Yoav Gaudin · Accepted Answer · 2018-04-01 13:42:41Z

0

How about this:

def fetchColors(x):
    color_keys = []
    for key, values in color.items():
        for value in values:
            if value in x.lower():
                color_keys.append(key)
    if color_keys:
        return '|'.join(color_keys)
    else:
        return np.nan

answered Apr 1, 2018 at 13:42

Yoav Gaudin

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