python - Pandas data frame from dictionary -

i have python dictionary of user-item ratings looks this:

sample={'user1': {'item1': 2.5, 'item2': 3.5, 'item3': 3.0, 'item4': 3.5, 'item5': 2.5, 'item6': 3.0},  'user2': {'item1': 2.5, 'item2': 3.0, 'item3': 3.5, 'item4': 4.0},  'user3': {'item2':4.5,'item5':1.0,'item6':4.0}} 

i looking convert pandas data frame structured like

     col1   col2  col3 0   user1  item1   2.5 1   user1  item2   3.5 2   user1  item3   3.0 3   user1  item4   3.5 4   user1  item5   2.5 5   user1  item6   3.0 6   user2  item1   2.5 7   user2  item2   3.0 8   user2  item3   3.5 9   user2  item4   4.0 10  user3  item2   4.5 11  user3  item5   1.0 12  user3  item6   4.0 

any ideas appreciated :)

try following code:

import pandas  sample={'user1': {'item1': 2.5, 'item2': 3.5, 'item3': 3.0, 'item4': 3.5, 'item5': 2.5, 'item6': 3.0},         'user2': {'item1': 2.5, 'item2': 3.0, 'item3': 3.5, 'item4': 4.0},         'user3': {'item2':4.5,'item5':1.0,'item6':4.0}}  df = pandas.dataframe([     [col1,col2,col3] col1, d in sample.items() col2, col3 in d.items() ])