pandas init dataframe 实例化

pandas init Dataframe

1, 使用字典init

>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> pd.DataFrame(data=d)
   col1  col2
0     1     3
1     2     4

另一种使用dict的方法from_dict

>>> d = {'col1': [1, 2], 'col2': [3, 4]}
>>> pd.DataFrame.from_dict(d)
   col1  col2
0     1     3
1     2     4

2, 使用numpy ndarray生成

>>> np_array = np.random.randint(low=0, high=10, size=(5, 5))
>>> np_array
array([[4, 4, 6, 6, 9],
       [3, 6, 9, 8, 0],
       [8, 8, 7, 4, 1],
       [8, 8, 5, 0, 4],
       [0, 8, 7, 1, 3]])
>>> pd.DataFrame(np_array)
   0  1  2  3  4
0  4  4  6  6  9
1  3  6  9  8  0
2  8  8  7  4  1
3  8  8  5  0  4
4  0  8  7  1  3

3，指定column和index

>>> columns=['2002','2003','2004','2005']
>>> index=['Zidane','Figo','Beckham','Totti']
>>> pd.DataFrame(columns=columns,index=index)
        2002 2003 2004 2005
Zidane   NaN  NaN  NaN  NaN
Figo     NaN  NaN  NaN  NaN
Beckham  NaN  NaN  NaN  NaN
Totti    NaN  NaN  NaN  NaN