使用pandas将列追加到列

Question

I have a dataset with the following structure, with varying sizes.:

A B C D E F G H I J
1 8 7 1 3 4 7 1 5 9 
8 9 1 4 7 4 5 2 1 2 
8 9 7 7 4 2 9 7 1 0 

What I want to do is append all columns to the first column and achieve a result like this:

A
1
8
8
8
9
9
7
1
7
1
7
...

My code so far: import pandas as pd

df = pd.read_csv("data.csv", header=None, delimiter=";")

for column in df:
    df.append(column)

print(df)

I figured it should work by looping over all columns and using .append to append them to the first column.

Any help is appreciated

Answer 1

I believe here is better use numpy , solution with numpy.ravel with transpose numpy array:

df = pd.DataFrame({'A':df.values.T.ravel()})
print (df)
    A
0   1
1   8
2   8
3   8
4   9
5   9
6   7
7   1
8   7
9   1
10  4
11  7
12  3
13  7
14  4
15  4
16  4
17  2
18  7
19  5
20  9
21  1
22  2
23  7
24  5
25  1
26  1
27  9
28  2
29  0

Answer 2

您可以使用reshape执行以下操作：

df = pd.DataFrame(df.values.reshape(-1), columns=['A'])

Answer 3

Maybe using melt

df.melt()
Out[72]: 
   variable  value
0         A      1
1         A      8
2         A      8
3         B      8
4         B      9
5         B      9
6         C      7
7         C      1
8         C      7
9         D      1
10        D      4
11        D      7
12        E      3
13        E      7
14        E      4
15        F      4
16        F      4
17        F      2
18        G      7
19        G      5
20        G      9
21        H      1
22        H      2
23        H      7
24        I      5
25        I      1
26        I      1
27        J      9
28        J      2
29        J      0