pandas 统计数据频率函数value_counts

value_counts默认参数如下：

value_counts(values, sort=True, ascending=False, normalize=False, bins=None, dropna=True)

1. ### Series类型

2. import pandas as pd

3. data=pd.Series(['python','java','python','php','php','java','python','java'])

4. print(data)

5. print('..........\n')

6. print(data.value_counts())

7. 0 python

8. 1 java

9. 2 python

10. 3 php

11. 4 php

12. 5 java

13. 6 python

14. 7 java

15. dtype: object

16. ............

17.  

18. python 3

19. java 3

20. php 2

1. ### DataFrame类型

2. import pandas as pd

3. data1={'key1':['python','java','python','php'],'key2':['php','java','python','SAS']}

4. b=pd.DataFrame(data1)

5. print(b)

6. print('............\n')

7. print(b.apply(pd.value_counts))

8. key1 key2

9. 0 python php

10. 1 java java

11. 2 python python

12. 3 php SAS

13. ............

14.  

15. key1 key2

16. SAS NaN 1

17. java 1.0 1

18. php 1.0 1

19. python 2.0 1