Copying column values up based on other column values

Copying column values up based on other column values - Printable Version

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Copying column values up based on other column values - codelines - Jan-03-2021

Hello,

I have this dataframe

import numpy as np
import pandas as pd
from numpy.random import randn
df=pd.DataFrame(randn(5,4),['A','B','C','D','E'],['W','X','Y','Z'])

Output:W	X	Y	Z
A	-0.183141	-0.398652	0.909746	0.332105
B	-0.587611	-2.046930	1.446886	0.167606
C	1.142661	-0.861617	-0.180631	1.650463
D	1.174805	-0.957653	1.854577	0.335818
E	-0.680611	-1.051793	1.448004	-0.490869

is there a way to create a column S - which will copy column column Y values UP- if values in column Y are above 1 - otherwise return new value above zero?.I made this manually:

Output:S:

A    1.446886
B    1.446886
C    1.854577
D    1.854577
E    1.448004

thanks a lot!

RE: Copying column values up based on other column values - codelines - Jan-03-2021

thank you - I included all the code...the last column S was manually created by me as a reference for the code required for this operation...in excel there is a quick way to back-propagate a cell value by making it equal to the next one - eg A10=A11 - is there a quick way to do that in pandas given that it operates on arrays?