import numpy as np
import pandas as pd
from pandas import Series, DataFramei
import pandas_datareader.data...value_counts():计算出现的频率,降序
pd.value_counts(obj.values, sort=False)
isin()判断成员资格
obj = pd.Series(['c'...值计数功能
uniques=obj.unique()
uniques
array(['c', 'a', 'd', 'b'], dtype=object)
obj.value_counts() # 默认是降序通过...sort=False关闭降序功能pd.value_counts(obj.values, sort=False)
a 3
c 3
b 2
d 1
dtype: int64
# 成员资格...将pandas.value_counts传给该DataFrame的apply函数
data = pd.DataFrame({'Qu1': [1, 3, 4, 3, 4],