Column order in pandas.concat

Question

I do as below:

data1 = pd.DataFrame({ \'b\' : [1, 1, 1], \'a\' : [2, 2, 2]})
data2 = pd.DataFrame({ \'b\' : [1, 1, 1], \'a\' : [2, 2, 2]})
frames = [data1, data2         


        

Answer 1

You can create the original DataFrames with OrderedDicts

from collections import OrderedDict

odict = OrderedDict()
odict['b'] = [1, 1, 1]
odict['a'] = [2, 2, 2]
data1 = pd.DataFrame(odict)
data2 = pd.DataFrame(odict)
frames = [data1, data2]
data = pd.concat(frames)
data


    b    a
0   1    2
1   1    2
2   1    2
0   1    2
1   1    2
2   1    2