numpy类型会出现如下情况,而pandas会自动转换数据类型
In [46]: tmp[0] = np.nan
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-46-1b66276310ce> in <module>
----> 1 tmp[0] = np.nan
ValueError: cannot convert float NaN to integer
numpy 有 mean() 方法 ,无 median() 方法
In [46]: tmp[0] = np.nan
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
<ipython-input-46-1b66276310ce> in <module>
----> 1 tmp[0] = np.nan
ValueError: cannot convert float NaN to integer
pandas的 Series, DataFrame 都有mean(),median()
In [54]: a = pd.Series(range(10))
In [55]: a
Out[55]:
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
dtype: int64
In [56]: a.mean()
Out[56]: 4.5
In [57]: a.median()
Out[57]: 4.5
numpy 如果包含 nan 均值计算 均值就是 nan
pandas 则会 跳过 nan