Here is a code:
# from: https://stackoverflow.com/questions/60101845/compare-multiple-pandas-columns-1st-and-2nd-after-3rd-and-4rth-after-etc-wit
# from: https://stackoverflow.com/questions/27474921/compare-two-columns-using-pandas?answertab=oldest#tab-top
# from: https://stackoverflow.com/questions/60099141/negation-in-np-select-condition
import pandas as pd
import numpy as np
df = pd.DataFrame({ 'var1': ['a', 'b', 'c',np.nan, np.nan],
'var2': [1, 2, np.nan , 4, np.nan],
'var3': [np.nan , "x", np.nan, "y", "z"],
'var4': [np.nan , 4, np.nan, 5, 6],
'var5': ["a", np.nan , "b", np.nan, "c"],
'var6': [1, np.nan , 2, np.nan, 3]
})
col1 = ["var1", "var3", "var5"]
col2 = ["var2", "var4", "var6"]
colR = ["Result1", "Result2", "Result3"]
s1 = df[col1].isnull().to_numpy()
s2 = df[col2].isnull().to_numpy()
conditions = [~s1 & ~s2, s1 & s2, ~s1 & s2, s1 & ~s2]
choices = ["Both values", np.nan, df[col1], df[col2]]
df = pd.concat([df, pd.DataFrame(np.select(conditions, choices), columns=colR, index=df.index)], axis=1)
The result ( df ) looks like:
var1 var2 var3 var4 var5 var6 Result1 Result2 Result3
0 a 1.0 NaN NaN a 1.0 Both values NaN Both values
1 b 2.0 x 4.0 NaN NaN Both values Both values NaN
2 c NaN NaN NaN b 2.0 c NaN Both values
3 NaN 4.0 y 5.0 NaN NaN 4 Both values NaN
4 NaN NaN z 6.0 c 3.0 NaN Both values Both values
It works but have problems with missing values in choices (more about it here, but it is not that important to my current question).
Now I need to use instead of np.select(conditions, choices) code something like this (the idea is to use pandas instead of numpy in order to avoid problems described in a link above):
pd.DataFrame(choices).where(conditions).ffill().fillna(0).iloc[-1]
or this:
pd.DataFrame(choices).where(conditions,0).sum()
If I just replace the code part I am getting error:
runfile('D:/del/untitlejhgd0.py', wdir='D:/del')
Traceback (most recent call last):
File "<ipython-input-16-10cdf307d77c>", line 1, in <module>
runfile('D:/del/untitlejhgd0.py', wdir='D:/del')
File "C:\ProgramData\Anaconda3\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 827, in runfile
execfile(filename, namespace)
File "C:\ProgramData\Anaconda3\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 110, in execfile
exec(compile(f.read(), filename, 'exec'), namespace)
File "D:/del/untitlejhgd0.py", line 29, in <module>
df = pd.concat([df, pd.DataFrame((pd.DataFrame(conditions).where(choices).ffill().fillna(0).iloc[-1]), columns=colR, index=df.index)], axis=1)
File "C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\frame.py", line 488, in __init__
mgr = init_ndarray(data, index, columns, dtype=dtype, copy=copy)
File "C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\internals\construction.py", line 169, in init_ndarray
values = prep_ndarray(values, copy=copy)
File "C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\internals\construction.py", line 295, in prep_ndarray
raise ValueError("Must pass 2-d input")
ValueError: Must pass 2-d input
Question: How to replace code parts above in order to make code work?
