Opposite function to utcfromtimestamp?

Question

What is the opposite function to utcfromtimestamp()?

timestamp() apparently does not take the timezone into account, as one can see in the following example:

import pandas as pd
import datetime
start = pd.datetime(2000, 1, 1, 0, 0, 0)
asFloat = start.timestamp()
startDifferent = datetime.datetime.utcfromtimestamp(asFloat)
startDifferent
Out[8]: datetime.datetime(1999, 12, 31, 23, 0)

Answer 1

utctimetuple --> calendar.timegm --> utcfromtimestamp forms a round-trip:

import calendar
import datetime as DT
start = DT.datetime(2000, 1, 1, 0, 0, 0)

utc_tuple = start.utctimetuple()
utc_timestamp = calendar.timegm(utc_tuple)
startDifferent = DT.datetime.utcfromtimestamp(utc_timestamp)
print(startDifferent)
# 2000-01-01 00:00:00

timestamp --> fromtimestamp also round-trips:

asFloat = start.timestamp()
startDifferent = DT.datetime.fromtimestamp(asFloat)
print(startDifferent)
# 2000-01-01 00:00:00

There is no utc equivalent of timestamp which goes directly from a datetime.datetime to a timestamp. The closest equivalent is calendar.timegm(date.utctimetuple()).

---

This roughly depicts the relationship between the methods:

                o------------o
                |            |  DT.datetime.utcfromtimestamp (*)
                |            |<-----------------------------------o
                |            |                                    |
                |            |  DT.datetime.fromtimestamp         |
                |  datetime  |<-------------------------------o   |
                |            |                                |   |
                |            |    .timestamp                  |   |
                |            |----------------------------o   |   | 
                |            |                            |   |   |
                o------------o                            |   |   |
                   |   ^                                  |   |   |
        .timetuple |   |                                  |   |   |
 .utctimetuple (*) |   | DT.datetime(*tup[:6])            |   |   |
                   v   |                                  v   |   |
                o------------o                          o------------o
                |            |-- calendar.timegm (*) -->|            |
                |            |                          |            |
                |            |---------- time.mktime -->|            |
                |  timetuple |                          |  timestamp |
                |            |<-- time.localtime -------|            |
                |            |                          |            |
                |            |<-- time.gmtime (*)-------|            |
                o------------o                          o------------o

(*) Interprets its input as being in UTC and returns output which should be interpreted as being in UTC.