代码
需要先导入pandas
arr的数据类型为一维的np.array
import pandas as pd
arr[~pd.isnull(arr)]
补充知识：python numpy.mean() axis参数使用方法【sum(axis=*)是求和，mean(axis=*)是求平均值】
如下所示：
import numpy as np
X = np.array([[1, 2], [4, 5], [7, 8]])
print(np.mean(X, axis=0, keepdims=True))
print('*'*50)
print(np.mean(X, axis=1, keepdi
