How to convert date string by using Lib 'dateutil'?

Question

When running dateutil.parser.parse("2017-09-19T04:31:43Z").strftime('%s') in Python, I obtain the following error:

ValueError: Invalid format string

What is the problem?

Answer 1

The same code works for me in Python 2.

from dateutil.parser import parse
print(parse("2017-09-19T04:31:43Z").strftime('%s'))
# 1505813503

or

import dateutil.parser
print(dateutil.parser.parse("2017-09-19T04:31:43Z").strftime('%s'))
# 1505813503

---

The OP claims that this does NOT work, giving the same ValueError: Invalid format string error.

One explanation is that, according to this post, your option %s doesn't exist. See valid options of time.strftime here.

Why did %s work on my system?

Great answer by Darren Stone from this post

In the Python source for datetime and time, the string STRFTIME_FORMAT_CODES tells us:

"Other codes may be available on your platform.
See documentation for the C library strftime function." 

So now if we man strftime (on BSD systems such as Mac OS X), you'll find support for %s:

%s is replaced by the number of seconds since the Epoch, UTC (see mktime(3))." 

What can you do?

It seems you want the Unix timestamp. As suggested by @jleahy here,

If you want to convert a python datetime to seconds since epoch you should do it explicitly:

datetime.datetime(2012,04,01,0,0).strftime('%s') # '1333234800'
(datetime.datetime(2012,04,01,0,0) - 
 datetime.datetime(1970,1,1)).total_seconds() # 1333238400.0 

In Python 3.3+ you can use timestamp() instead:

datetime.datetime(2012,4,1,0,0).timestamp() # 1333234800.0