Pandas - Create a DF with all the values from 2 columns

Question

I have a DF similar to the below. What I want to do is to take the SKUs from SKU1 and SKU2 and create a separate DF with all possible SKU values. It seems simple but I'm having some trouble.

DF

SKU1	SKU2
66FS	6dhs
b87w	ssftv
yy5hf
	y346d

Desired Output

All_SKUs
66FS
b87w
yy5hf
6dhs
ssftv
y346d

Answer 1

If order doesn't matter, stack :

out = df.stack().droplevel(1).to_frame(name='All_SKUs')

output:

  All_SKUs
0     66FS
0     6dhs
1     b87w
1    ssftv
2    yy5hf
3    y346d

Else, melt :

out = df.melt(value_name='All_SKUs').dropna().drop(columns='variable')

output:

  All_SKUs
0     66FS
1     b87w
2    yy5hf
4     6dhs
5    ssftv
7    y346d