pandas datetime to unix timestamp seconds

I think you misunderstood what the argument is for. The purpose of origin='unix' is to convert an integer timestamp to datetime, not the other way.

pd.to_datetime(1.547559e+09, unit='s', origin='unix') 
# Timestamp('2019-01-15 13:30:00')

Here are some options:

Option 1: integer division

Conversely, you can get the timestamp by converting to integer (to get nanoseconds) and divide by 10⁹.

pd.to_datetime(['2019-01-15 13:30:00']).astype(int) / 10**9
# Float64Index([1547559000.0], dtype='float64')

Pros:

• super fast

Cons:

• makes assumptions about how pandas internally stores dates

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Option 2: recommended by pandas

Pandas docs recommend using the following method:

# create test data
dates = pd.to_datetime(['2019-01-15 13:30:00'])

# calculate unix datetime
(dates - pd.Timestamp("1970-01-01")) // pd.Timedelta('1s')

[out]:
Int64Index([1547559000], dtype='int64')

Pros:

• "idiomatic", recommended by the library

Cons:

• unweildy
• not as performant as integer division

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Option 3: pd.Timestamp

If you have a single date string, you can use pd.Timestamp as shown in the other answer:

pd.Timestamp('2019-01-15 13:30:00').timestamp()
# 1547559000.0

If you have to cooerce multiple datetimes (where pd.to_datetime is your only option), you can initialize and map:

pd.to_datetime(['2019-01-15 13:30:00']).map(pd.Timestamp.timestamp)
# Float64Index([1547559000.0], dtype='float64')

Pros:

• best method for a single datetime string
• easy to remember

Cons:

• not as performant as integer division

value attribute of the pandas Timestamp holds the unix epoch. This value is in nanoseconds. So you can convert to ms or us by diving by 1e3 or 1e6. Check the code below.

import pandas as pd
date_1 = pd.to_datetime('2020-07-18 18:50:00')
print(date_1.value) 

You can use timestamp() method which returns POSIX timestamp as float:

pd.Timestamp('2021-04-01').timestamp()

[Out]:
1617235200.0

pd.Timestamp('2021-04-01 00:02:35.234').timestamp()

[Out]:
1617235355.234