value_counts()

• value_counts()是一种查看表格某列中有多少个不同值的快捷方法，并计算每个不同值有在该列中有多少重复值。

import pandas as pd
import numpy as np
df1= DataFrame(
                {"handsome":["timo","anni","timo"],
                "smart":["mike","anni","mike"]}
                )
print(df1)
'''
  handsome smart
0     timo  mike
1     anni  anni
2     timo  mike
'''
 
df1.apply(pd.value_counts)##数据框要借助apply来应用value_counts()
'''
	   handsome	smart
anni	1.0	     1.0
mike	NaN	     2.0
timo	2.0	     NaN
'''
 
import pandas as pd
import numpy as np
from pandas import DataFrame
from pandas import Series
s1=Series(["timo","mike","anni","timo"])
s1.value_counts()
'''
timo    2
mike    1
anni    1
dtype: int64
'''