python - Convert dataFrame to list

Question

I have a pandas dataframe that I convert to numpy array as follows:

df.values

which gives the following output:

array([[2],
       [0],
       [1],
       ..., 
       [0],
       [1],
       [0]], dtype=int64)

However I want to obtain the list as follows:

[0, 2, 3]

Any idea how to do this?

Answer 1

Maybe you can use iloc or loc for selecting column and then tolist:

print df
   a
0  2
1  0
2  1
3  0
4  1
5  0

print df.values
[[2]
 [0]
 [1]
 [0]
 [1]
 [0]]

print df.iloc[:, 0].tolist()
[2, 0, 1, 0, 1, 0]

Or maybe:

print df.values.tolist()
[[2L], [0L], [1L], [0L], [1L], [0L]]

print df.iloc[:, 0].values.tolist()
[2L, 0L, 1L, 0L, 1L, 0L]

print df.loc[:, 'a'].tolist()
[2, 0, 1, 0, 1, 0]

print df['a'].tolist()
[2, 0, 1, 0, 1, 0]

But maybe you need flatten:

print df.values.flatten()
[2 0 1 0 1 0]

print df.iloc[:, 0].values.flatten()
[2 0 1 0 1 0]