pandas pandas中datetime和datetime64[ns]的比较

Comparison between datetime and datetime64[ns] in pandas

提问by JesusMonroe

I'm writing a program that checks an excel file and if today's date is in the excel file's date column, I parse it

我正在编写一个检查 excel 文件的程序，如果今天的日期在 excel 文件的日期列中，我会解析它

I'm using:

我正在使用：

cur_date = datetime.today()

for today's date. I'm checking if today is in the column with:

对于今天的日期。我正在检查今天是否在列中：

bool_val = cur_date in df['date'] #evaluates to false

I do know for a fact that today's date is in the file in question. The dtype of the series is datetime64[ns]

我确实知道今天的日期在相关文件中。该系列的 dtype 是 datetime64[ns]

Also, I am only checking the date itself and not the timestamp afterwards, if that matters. I'm doing this to make the timestamp 00:00:00:

另外，如果这很重要，我只检查日期本身而不是之后的时间戳。我这样做是为了使时间戳为 00:00:00：

cur_date = datetime.strptime(cur_date.strftime('%Y_%m_%d'), '%Y_%m_%d')

And the type of that object after printing is datetime as well

打印后该对象的类型也是日期时间

回答by piRSquared

You can use

您可以使用

pd.Timestamp('today')

or

或者

pd.to_datetime('today')

But both of those give the date and time for 'now'.

但是这两个都给出了 的日期和时间'now'。

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Try this instead:

试试这个：

pd.Timestamp('today').floor('D')

or

或者

pd.to_datetime('today').floor('D')

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You could have also passed the datetimeobject to pandas.to_datetimebut I like the other option mroe.

您也可以将datetime对象传递给，pandas.to_datetime但我喜欢另一个选项 mroe。

pd.to_datetime(datetime.datetime.today()).floor('D')

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Pandas also has a Timedeltaobject

Pandas也有Timedelta对象

pd.Timestamp('now').floor('D') + pd.Timedelta(-3, unit='D')

Or you can use the offsetsmodule

或者你可以使用offsets模块

pd.Timestamp('now').floor('D') + pd.offsets.Day(-3)

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To check for membership, try one of these

要检查会员资格，请尝试其中之一

cur_date in df['date'].tolist()

Or

或者

df['date'].eq(cur_date).any()