简单地传递所期望的值作为第一个参数,如0
,math.inf
或,这里,np.nan
。然后,构造函数将值数组初始化并填充为参数index
和指定的大小columns
:
>>> import numpy as np
>>> import pandas as pd
>>> df = pd.DataFrame(np.nan, index=[0, 1, 2, 3], columns=['A', 'B'])
>>> df.dtypes
A float64
B float64
dtype: object
>>> df.values
array([[nan, nan],
[nan, nan],
[nan, nan],
[nan, nan]])