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pythonpandasif-statementconditional-statements
jeangelj
jeangelj

Reputation: 4498

Python panda overwrite value based on conditional in other column

Working with the dataframe df in python pandas:

Product_ID  | Category  | Sub_Cat
32432           0         Gadget
24085         Big Tech    Computer
54398         Small Tech  Gadget
97456           0         Computer

I am working on a new column, where I will over-write the Sub_Cat value with the Category value, if it is not 0.

This is the output I am looking for:

Product_ID  | Category  | Sub_Cat         | Cat_for_Analysis
32432           0         Gadget            Gadget
24085         Big Tech    Computer          Big Tech
54398         Small Tech  Gadget            Small Tech
97456           0         Computer          Computer

Thank You!

Upvotes: 0

Views: 151

Answers (3)

quantik
quantik

Reputation: 816

You could use apply for this too.

df["Cat_for_Analysis"] = df.apply(lambda row: row["Category"] if row["Category"] != 0 else row["Sub_Cat"], axis=1)

Upvotes: 1

root
root

Reputation: 33793

Using np.where:

df['Cat_for_Analysis'] = np.where(df['Category'] == '0', df['Sub_Cat'], df['Category'])

Or equivalently the negated version, if it makes more intuitive sense based on your problem:

df['Cat_for_Analysis'] = np.where(df['Category'] != '0', df['Category'], df['Sub_Cat'])

The resulting output for either method:

   Product_ID    Category   Sub_Cat Cat_for_Analysis
0       32432           0    Gadget           Gadget
1       24085    Big Tech  Computer         Big Tech
2       54398  Small Tech    Gadget       Small Tech
3       97456           0  Computer         Computer

Upvotes: 1

BENY
BENY

Reputation: 323246

You can using ffill after replace '0' to np.nan

df['Cat_for_Analysis']=df.replace('0',np.nan)[['Category','Sub_Cat']].bfill(1).iloc[:,0]
df
Out[876]: 
   Product_ID   Category   Sub_Cat Cat_for_Analysis
0       32432          0    Gadget           Gadget
1       24085    BigTech  Computer          BigTech
2       54398  SmallTech    Gadget        SmallTech
3       97456          0  Computer         Computer

Upvotes: 1

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