CODEWITHSUNDEEP
pythonpandas
user2475110
user2475110

Reputation: 381

Conditional transform of a Series subset in Pandas

What is the cleanest way to do the following transformation in Pandas (Python) :

number   color
 10      blue
 15      red
 25      green
 35      blue
 15      pink
 30      green
  5      red
 20      blue
 50      red

into 

number   color
 10      blue
 15      FALSE
 25      FALSE
 35      blue
 15      FALSE
 30      green
  5      FALSE
 20      blue
 50      red

Essentially, I'd like to change all colors whose number is < 30 but that rule only applies if the color IS NOT blue.

Thanks !

Upvotes: 2

Views: 312

Answers (2)

Chief
Chief

Reputation: 11

Instead of map, you can use "apply". Apply runs the function on each row.

def mod_color(row) : 
    if row.number < 30 and row.color != 'blue': 
        row.color = False
    return row

df.apply(mod_color, axis=1)

Upvotes: 1

Divakar
Divakar

Reputation: 221584

One approach -

df.loc[(df.number < 30) & (df.color != 'blue'),'color'] = False

Sample run -

In [409]: df
Out[409]: 
   number  color
0      10   blue
1      15    red
2      25  green
3      35   blue
4      15   pink
5      30  green
6       5    red
7      20   blue
8      50    red

In [410]: df.loc[(df.number < 30) & (df.color != 'blue'),'color'] = False

In [411]: df
Out[411]: 
   number  color
0      10   blue
1      15  False
2      25  False
3      35   blue
4      15  False
5      30  green
6       5  False
7      20   blue
8      50    red

Upvotes: 2

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