给定另一列包含特定值的 Pandas 行数

Question

I'm brand new to pandas and I have a csv file which i have read in with csv_read with pandas eg. I have read it in as b = pandas.read_csv('BLA.csv')

|  Gender  |  ID   |
|     M    |   D   |
|     F    |   P   |
|     M    |   P   |
|     F    |   D   |
|     M    |   D   |
|     F    |   D   |

how do I go about counting the number of occurrences of the Genders given the ID status of the person is D?

Answer 1

Try this:

b['tmp'] = 1
b.groupby(['Gender', 'ID']).count().query('ID == "D"')