matrix - Python - pandas - Append Series into Blank DataFrame -

say have 2 pandas series in python:

import pandas pd h = pd.series(['g',4,2,1,1]) g = pd.series([1,6,5,4,"abc"]) 

i can create dataframe h , append g it:

df = pd.dataframe([h]) df1 = df.append(g, ignore_index=true) 

i get:

>>> df1    0  1  2  3    4 0  g  4  2  1    1 1  1  6  5  4  abc 

but suppose have empty dataframe , try append h it:

df2 = pd.dataframe([]) df3 = df2.append(h, ignore_index=true) 

this not work. think problem in second-to-last line of code. need somehow define blank dataframe have proper number of columns.

by way, reason trying scraping text internet using requests+beautifulsoup , processing , trying write dataframe 1 row @ time.

so if don't pass empty list dataframe constructor works:

in [16]:  df = pd.dataframe() h = pd.series(['g',4,2,1,1]) df = df.append(h,ignore_index=true) df out[16]:    0  1  2  3  4 0  g  4  2  1  1  [1 rows x 5 columns] 

the difference between 2 constructor approaches appears index dtypes set differently, empty list int64 nothing object:

in [21]:  df = pd.dataframe() print(df.index.dtype) df = pd.dataframe([]) print(df.index.dtype) object int64 

unclear me why above should affect behaviour (i'm guessing here).

update

after revisiting can confirm looks me bug in pandas version 0.12.0 original code works fine:

in [13]:  import pandas pd df = pd.dataframe([]) h = pd.series(['g',4,2,1,1]) df.append(h,ignore_index=true)  out[13]:    0  1  2  3  4 0  g  4  2  1  1  [1 rows x 5 columns] 

i running pandas 0.13.1 , numpy 1.8.1 64-bit using python 3.3.5.0 think problem pandas upgrade both pandas , numpy safe, don't think 32 versus 64-bit python issue.