Find and replace a duplicate value in pandas DF

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I have the below df in pandas:

enter image description here

I need to find the duplicate value, in this case the number 1 in the index 2 and apply the formula ma.trunc(ma.pow(x,2))+1 and after replace the value result in the index 2 where the number 1 was.

Any help will be highly appreciated.

pandas python
1 Answers

You can locate all of the duplicates with the duplicated() command. Note that keep="first" (default value) will prevent the first occurence from being marked as a duplicate.

is_dup = df.duplicated(subset="Enrollment", keep="first")

Then you can apply a custom function to the values that are duplicated with the where() and map() functions.

my_func = lambda x: ma.trunc(ma.pow(x,2))+1
df["Enrollment"] = df["Enrollment"].where( ~is_dup, df["Enrollment"].map( my_func ))
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