Using map with variable

Question

I have str list

startDateTimes = ["2011/12/13 00:00","2011/12/13 03:00","2011/12/15 05:00"]
datetime.datetime.strptime(startDateTimes[0],'%Y/%m/%d %H:%M')

Now I want to use strptime for all items in list.

I think I should use map though, still not clear to me.

For example

map(datetime.datetime.strptime,startDateTimes)

Where should I put %Y/%m/%d %H:%M?

I consider closing of the question a bit harsh without additional explanation. As I understand, the approach suggest in the linked question is, to call map with 3 arguments, the `strptime` function, an iterator delivering the data format (e. g. `itertools.repeat`) and the startDateTimes list. — guidot, Jan 07 '22 at 10:27
Yes, Maybe it is me not getting the rules 100% and I agree that some questions would require minimal effort to find an answer but, at the end of the day, it is a "help" forum and not a book. I myself think this did not deserve to be closed - for what it counts :-) — nikeros, Jan 09 '22 at 12:03

nikeros · Accepted Answer · 2022-01-07T09:30:31.943

1

Why not a list comprehension?

[datetime.datetime.strptime(x, '%Y/%m/%d %H:%M') for x in startDateTimes]

You could use map like this:

def parse(x): return datetime.datetime.strptime(x, '%Y/%m/%d %H:%M')

list(map(parse, startDateTimes))

OUTPUT

[datetime.datetime(2011, 12, 13, 0, 0), datetime.datetime(2011, 12, 13, 3, 0), datetime.datetime(2011, 12, 15, 5, 0)]

You could clearly have a one-liner and move the definition of the parse function as a lambda within map - just wanted to make it clearer.

edited Jan 07 '22 at 09:30

answered Jan 07 '22 at 09:18

nikeros

THank you , i use comprehension, it works well for this purpose. Using `map` needs two lines. – whitebear Jan 09 '22 at 11:02

score 1 · Answer 2 · answered Jan 07 '22 at 09:21

1

You can use a lambda here

map(lambda dt: datetime.datetime.strptime(dt,'%Y/%m/%d %H:%M'),startDateTimes)

answered Jan 07 '22 at 09:21

Simon Hawe

score 1 · Answer 3 · edited Jan 07 '22 at 09:40

1

You can use functools.partial for this, it allows you to create a function which will apply given arguments by default. Example:

from functools import partial

dates = map(partial(datetime.datetime.strptime, format='%Y/%m/%d %H:%M'), startDateTimes)

edited Jan 07 '22 at 09:40

guidot

answered Jan 07 '22 at 09:21

Paradoxis

3 Answers3