Append list to an existing dataframe as a column

Question

I have a pandas dataframe as below

df = [['A',1],
        ['A',1],
        ['A',0],
        ['A',0],
        ['A',5],
        ['B',0],
        ['B',0],
        ['B',1],
        ['B',1]] 

df = pd.DataFrame(df, columns = ['A', 'B'])
df

    A   B
0   A   1
1   A   1
2   A   0
3   A   0
4   A   5
5   B   0
6   B   0
7   B   1
8   B   1

I have a list of items as below. I want to append 'new_list ' into my 'df' dataframe as column C

new_list = [[1], [1], [1], [1], [5], [0], [0], [1], [1]]

Answer 1

Try using .join() like so:

df = df.join(pd.DataFrame({'C': new_list}))

df:

    A   B   C
0   A   1   1
1   A   1   1
2   A   0   1
3   A   0   1
4   A   5   5
5   B   0   0
6   B   0   0
7   B   1   1
8   B   1   1

Note you need to turn your list into a data frame for this to work.

Answer 2

try using numpy method .flatten()

df['C'] = numpy.asarray(new_list).flatten()


df

   A  B  C
0  A  1  1
1  A  1  1
2  A  0  1
3  A  0  1
4  A  5  5
5  B  0  0
6  B  0  0
7  B  1  1
8  B  1  1

Answer 3

IIUC

df['C']=sum(new_list,[])
df
Out[8]: 
   A  B  C
0  A  1  1
1  A  1  1
2  A  0  1
3  A  0  1
4  A  5  5
5  B  0  0
6  B  0  0
7  B  1  1
8  B  1  1

Or

import itertools
df['C']=list(itertools.chain(*new_list))