[FIXED] String ISIN another data frame returns nothing

Issue

I have a dataframe DF

Name	Code	Color
Test	1	red
Test2	1	blue
Test3	2	red
Test4	3	blue
Test5	3	black

I did the following code :

DFN = DF.loc[DF['Code'].isin(['1'])].reset_index(drop=True)
DFCode = DF.loc[DF['Color'].isin(DFN['Color'].values.tolist())].reset_index(drop=True)

This does return nothing, what am I doing wrong ? The output excepted would be :

Name	Code	Color
Test	1	red
Test2	1	blue
Test3	2	red
Test4	3	blue

Note : I don't know the color that I will be looking for and this is why I need to identify the Colors using the Code Column

Solution

As in the comments already suggested, you need to check if the values in the Code columns are integers or strings. Probably there is the problem.

If you just look for one value you can just filter with ==, no need for isin.

Use pandas.unique to check for all occuring values in a column, it's just a little more straightforward than values.tolist().

DFN = DF[DF['Code']==1] # or DFN = DF[DF['Code']=='1']
DFCode = DF.loc[DF['Color'].isin(DFN['Color'].unique())]
print(DFCode)

    Name  Code Color
0   Test     1   red
1  Test2     1  blue
2  Test3     2   red
3  Test4     3  blue

Answered By - Rabinzel