How to Convert Datetime64 to Datetime.Datetime or Timestamp in NumPy

1. the Problem
2. Convert datetime.datetime to np.datetime64 and pd.Timestamp
3. Convert np.datetime64 to datetime.datetime and pd.Timestamp
4. Convert Timestamp to datetime and datetime64

This article aims to demonstrate how to convert data between numPy.datetim64, datetime.datetime and Timestamp.

the Problem

When dealing with data - be it ordered or unordered, coming across date and time is a fairly common occurrence. Depending on the situation, the time and date must be dealt with in a suitable manner to ensure that the processed data is in a desirable format.

Code Example:

import datetime
import numpy as np
import pandas as pd

dt = datetime.datetime(2022, 5, 21)
ts = pd.DatetimeIndex([dt])[0]
dt64 = np.datetime64(dt)

In the code above, we have imported three modules named datetime, numpy, and pandas, each providing their implementation for storing and processing dates (each has its own distinct use cases).

Using datetime.datetime(), we create a datetime instance and store it in a variable named dt. As for pandas, we used the method pd.DatetimeIndex(), which creates an immutable array storing n number of datetime64 instances and accessing the first member of the array returns a Timestamp instance.

Coming to the pandas module, we use the datetime64() method to convert the datetime instance and store it in a variable named dt64.

It is easy to convert datetime to Timestamp and datetime64 instances. In this article, we will now see how we can convert np.datetime64 to datetime and Timestamp instances.

Convert datetime.datetime to np.datetime64 and pd.Timestamp

Code Example:

import datetime
import numpy as np
import pandas as pd

dt = datetime.datetime(
    year=2018, month=10, day=24, hour=4, minute=3, second=10, microsecond=7199
)

# convert datetime.datetime to np.datetim364
print(np.datetime64(dt))

# datetime.datetime to pd.Timestamp
print(pd.Timestamp(dt))

Output:

2018-10-24T04:03:10.007199
2018-10-24 04:03:10.007199

Convert datetime. datetime to datetime64 and Timestamp by passing the datetime instance to the constructors of datetime64 and Timestamp, which will be converted.

Convert np.datetime64 to datetime.datetime and pd.Timestamp

Code Example:

import datetime
import numpy as np
import pandas as pd

# np.datetime64 to datetime.datetime
dt64 = np.datetime64("2017-10-24 05:34:20.123456")
unix_epoch = np.datetime64(0, "s")
one_second = np.timedelta64(1, "s")
seconds_since_epoch = (dt64 - unix_epoch) / one_second

print(datetime.datetime.utcfromtimestamp(seconds_since_epoch))

# np.datetime64 to Timestamp
print(pd.Timestamp(dt64))

Output:

2017-10-24 05:34:20.123456
2017-10-24 05:34:20.123456

To convert from np.datetime64 to datetime.datetime, we must first convert the datetime64 data to seconds (in epoch format). After conversion, the seconds are passed to the datetime method named utcfromtimestamp, which reads the epoch time and converts it to an instance of datetime.

As for np.datetime64 to Timestamp, it is relatively simple, just pass the np.datetime64 instance to the Timestamp constructor.

Convert Timestamp to datetime and datetime64

Code Example:

import datetime
import numpy as np
import pandas as pd

ts = pd.Timestamp("2017-10-24 04:24:33.654321")

# Timestamp to datetime.datetime
print(ts.to_pydatetime())

# Timestamp to np.datetime64
print(ts.to_datetime64())

Output:

2017-10-24 04:24:33.654321
2017-10-24T04:24:33.654321000

With the help of these functions, Timestamp can be easily converted to datetime and datetime64 with just a single method call. To convert from Timestamp to datetime.datetime, use the to_pydatetime() method, It converts the Timestamp instance to a datetime. datetime instance.

As for conversion from Timestamp to datetime, use the to_datetime64() method. It converts the Timestamp instance to an np.datetime64 instance.