pandas 熊猫数据框。按值和计数分组
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Pandas dataframe. Group by value and count
提问by Jerry
I have the following table:
我有下表：
Days, Age, Sex
5, 39, F
4, 54, M
4, 26, M
5, 42, M
4, 29, M
I want to count number of rows with F and M separately. The following command works, but I'm not OK with the representation:
我想分别用 F 和 M 计算行数。以下命令有效，但我对表示不满意：
df.groupby("Sex").count()
What will be the best way to do it? Thank you.
最好的方法是什么？谢谢你。
回答by Tai
Just to add to Wen's answer. Alternatively, you can use value_countswhile selecting the column with df.Sex.
只是为了补充温的回答。或者，您可以在使用value_counts选择列时使用df.Sex。
df.Sex.value_counts()
M 4
F 1
Name: Sex, dtype: int64
