Pandas Convert Timestamp Column to Datetime

问题

Given the following data frame and necessary wrangling:

import pandas as pd
df=pd.DataFrame({'A':['a','b','c'],
        'dates':['2015-08-31 00:00:00','2015-08-24 00:00:00','2015-08-25 00:00:00']})
df.dates=df.dates.astype(str)
df['dates'] = pd.to_datetime(df.dates.str.split(',\s*').str[0])
set(df['dates'])

I end up with:

{Timestamp('2015-08-24 00:00:00'),
 Timestamp('2015-08-25 00:00:00'),
 Timestamp('2015-08-31 00:00:00')}

I need to convert the time stamps back to datetime (really, just date) format.

I've tried this based on the answer to this post:

df['dates'].to_pydatetime()

But that returns:

AttributeError: 'Series' object has no attribute 'to_pydatetime'

In my real data, the data type is: <M8[ns]

回答1:

You can use dt.date to return a datetime.date object:

In [3]:
set(df['dates'].dt.date)

Out[3]:
{datetime.date(2015, 8, 24),
 datetime.date(2015, 8, 25),
 datetime.date(2015, 8, 31)}

回答2:

If you are keen on extracting only the date from a given Timestamp object, you can get the raw datetime.date objects by calling the unbound Timestamp.date method as shown:

import pandas as pd
from pandas import Timestamp, Series, date_range

start = Timestamp('2016-01-01')
stop = Timestamp('2016-01-02')
s = Series(date_range(start, stop, freq = 'H'))

print s[0]
2016-01-01 00:00:00

print s.map(Timestamp.date)[0]
2016-01-01
dtype: object

回答3:

I have a similar issue where I need to convert timestamp to datetime in numpy though, but I believe it can be apply in Pandas as well. I think using function under Pandas.Timestamp would be better to convert timestamp as below.

==============================

np1=pd.DataFrame.to_numpy(df2)
print(np1)
[[Timestamp('2019-01-31 00:00:00') 'UCHITEC'  2000 2.56 5129.54]
 [Timestamp('2019-01-16 00:00:00') 'UCHITEC'  1000 2.61 2618.79]]

np2= np.asarray(np1)
Timestamp('2019-01-16 00:00:00')

np3 = pd.Timestamp.to_datetime64(np2[0][0])
np4 = pd.Timestamp.to_pydatetime(np2[1][0])

print(np3)
print(np4)

2019-01-31T00:00:00.000000000
2019-01-16 00:00:00

来源：https://stackoverflow.com/questions/37644199/pandas-convert-timestamp-column-to-datetime

标签

python-3.x

datetime

timestamp