CODEWITHSUNDEEP
pythonpandas
nia4life
nia4life

Reputation: 363

Subtracting pandas columns

Apologies I'm a python noob and I'm super rusty. Just getting back into code. Need help.

I have a dataframe (df) that looks like this:

        2020-10-21 2020-09-30 2020-08-31 2020-07-31 2020-06-30 2020-05-29
close   513.19     470.11     325.10     253.91     253.54     179.48

I'm trying to add a new column that calculates the difference between the most recent column (2020-10-21) and the last column (2020-05-29).

df['Val_Diff'] = df[0] - df[5]

print(df)

When it runs I'm getting the following error.


KeyError: 0

What's the right way to do this?

Upvotes: 0

Views: 48

Answers (1)

Roim
Roim

Reputation: 3066

If you are talking about columns' index (instead of name). use df.iloc[:,0] - df.iloc[:,5].

iloc receive index while loc receive column name. Also, loc and iloc are looking for [rows, columns], hence to choose all rows in a specific column: .iloc[:, column_index]

Upvotes: 1

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