CODEWITHSUNDEEP
pythonpandaspandas-loc
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Reputation: 101

Update Pandas df Given String Query

As a result of data introduced by users in the interface I have a string query-like. 

query = '(ColA=="7") & (ColB=="3") & (ColC=="alpha") & (ColD=="yu")'

Now I want to update a column of the df based on those conditions, assigning it a variable Z.

I don't know if it can be done somehow with loc 

df.loc[query, 'ColZ'] = Z

Upvotes: 6

Views: 1783

Answers (2)

BENY
BENY

Reputation: 323266

Yes that can be done with query

df.loc[df.query(query).index,'ColZ']=Z

Upvotes: 6

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Reputation: 101

I got the solution by myself:

df.loc[df.eval(query), 'ColZ'] = Z

https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.eval.html

Upvotes: 1

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