如何使用 Pandas 按月、日、年过滤
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How to filter by month, day, year with Pandas
提问by user3445881
I create the DataFrame with:
我使用以下命令创建数据帧：
df = pandas.read_csv("data.csv", sep=';', parse_dates = 1, dayfirst = True)
df = pandas.read_csv("data.csv", sep=';', parse_dates = 1, dayfirst = True)
I then get the following results:
然后我得到以下结果：
Qty System_created Total
0 2 2014-10-14 08:13:46.000 21.76
1 1 2014-10-14 08:13:46.000 4.16
2 2 2014-10-14 08:30:46.000 27.90
3 1 2014-10-14 08:30:46.000 4.95
4 1 2014-10-14 08:30:46.000 4.95
5 2 2014-11-05 11:15:47.000 21.76
6 1 2014-11-05 11:15:48.000 3.32
But I do not know how to filter by month(or year, day, hour etc...). Something like df[df["System_created"].day]would be ideal. Is that possible?
但我不知道如何按月（或年、日、小时等）过滤。像df[df["System_created"].day]这样的东西是理想的。那可能吗？
回答by EdChum
So long as your pandas version is 0.15or higher then the following would work assuming your dtypeis already a datetime:
只要您的 Pandas 版本是0.15或更高，那么假设您dtype已经是日期时间，则以下内容将起作用：
In [167]:
df[df.System_created.dt.day == 5]
Out[167]:
Qty System_created Total
index
5 2 2014-11-05 11:15:47 21.76
6 1 2014-11-05 11:15:48 3.32
So basically the dtattribute allows you to access the components of your datetime to perform the comparisons you desire for filtering
所以基本上该dt属性允许您访问日期时间的组件以执行您想要过滤的比较
