CODEWITHSUNDEEP
pythonpandasdataframe
Asheet_s
Asheet_s

Reputation: 19

Add a column based on values present in another column

I have a dataframe as:

id Value
0 Auto
1 Manual
2 Auto
3 Manual
4 Manual

I want to add another column based on values present in second column as:

id Value Flag
0 Auto Yes
1 Manual
2 auto Yes
3 manual
4 Manual

I tried below code:

mask = df['Purchase Order Num'].str.contains('Auto', na= False, case=False)
df['Flag'] = np.where(df[mask], 'Yes', '')

I get the error as :

Length of values (2) does not match length of index (5)

What went wrong?

Upvotes: 0

Views: 54

Answers (1)

BENY
BENY

Reputation: 323226

When we doing the np.where we need pass the whole Boolean to it

mask = df['Purchase Order Num'].str.contains('Auto', na= False, case=False)
df['Flag'] = np.where(mask, 'Yes', '')

pandas assign can do

df['Flag'] = ''
df.loc[mask, 'Flag'] = 'Yes'

Upvotes: 2

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