Pandas DataFrame column concatenation

Question

I have a pandas Dataframe y with 1 million rows and 5 columns.

np.shape(y)  
(1037889, 5)

The column values are all 0 or 1. Looks something like this:

y.head()  
a, b, c, d, e  
0, 0, 1, 0, 0  
1, 0, 0, 1, 1  
0, 1, 1, 1, 1  
0, 0, 0, 0, 0

I want a Dataframe with 1 million rows and 1 column.

np.shape(y)  
(1037889, )

where the column is just the 5 columns concatenated together.

New column  
0, 0, 1, 0, 0  
1, 0, 0, 1, 1  
0, 1, 1, 1, 1  
0, 0, 0, 0, 0

I keep trying different things like merge, concat, dstack, etc... but can't seem to figure this out.

Answer 1

If you want new column to have all data concatenated to string, it's good case for apply() function:

>>> df = pd.DataFrame({'a':[0,1,0,0], 'b':[0,0,1,0], 'c':[1,0,1,0], 'd':[0,1,1,0], 'c':[0,1,1,0]})
>>> df
   a  b  c  d
0  0  0  0  0
1  1  0  1  1
2  0  1  1  1
3  0  0  0  0
>>> df2 = df.apply(lambda row: ','.join(map(str, row)), axis=1)
>>> df2
0    0,0,0,0
1    1,0,1,1
2    0,1,1,1
3    0,0,0,0