TIMESTAMP format conversion in python

Question

How efficiently I can convert

date_format = "2019-01-30-10-07-50-000"

Expected output

"2019-01-30 10-07-50.000"

So far what I have tried :

ss = list(ss)
ss[10] = " "
ss[-4] = "."
print("".join(ss))

I Know i can do it using positional replacement using str replace() method, IS there any other efficient pythonic way , both are timestamps

Answer 1

date_format = "2019-01-30-10-07-50-000"
import datetime

d = datetime.datetime.strptime(date_format,"%Y-%m-%d-%H-%M-%S-000")
print(d.strftime("%Y-%d-%m %H-%M-%S.000"))