计算操作
1、pandas.series.value_counts
Series.value_counts(normalize=False,sort=True,ascending=False, bins...["a","b","c","d"],
columns=["one","two"])
print("df:")
print(df)
#直接使用sum()方法,返回一个列求和的...2、pandas.dataframe.mean
返回指定轴上值的平均数...."a","b","c","d"],
columns=["one","two"])
print("df:")
print(df)
#直接使用mean()方法,返回一个列求平均数的...na_position : {‘first’, ‘last’}, default ‘last’
first puts NaNs at the beginning, last puts NaNs at
