Format comma seperated list of dates in python

Question

I've got a list of dates (datetimes):

>>> print str(range)
[datetime.datetime(2011, 12, 15, 0, 0), datetime.datetime(2011, 12, 16, 0, 0), datetime.datetime(2011, 12, 17, 0, 0)]

and I'd like to format them as "%d/%m/%Y" and comma separate them, ie:

15/12/2011, 16/12/2011, 17/12/2011

At the moment I'm using map to run strftime on each of the dates like so:

>>> string = ", ".join(map(lambda x: x.strftime("%d/%m/%Y"), range))
>>> print string

which outputs:

15/12/2011, 16/12/2011, 17/12/2011

Ta dah!

It's not the easiest to read, but it works. Is it efficient? Is it pythonic? (does that matter?)

Ignacio Vazquez-Abrams · Accepted Answer · 2012-01-04 05:37:10Z

2

map() is considered deprecated (although there are those that will argue otherwise).

", ".join(x.strftime("%d/%m/%Y") for x in daterange)

answered Jan 4, 2012 at 5:37

Ignacio Vazquez-Abrams

804k160 gold badges1.4k silver badges1.4k bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Tadeck Over a year ago

Why "map() is considered deprecated"? Could you provide a source?

Greg Hewgill Over a year ago

I'm going to argue otherwise on that point, simply because map() still exists in Python 3.2 with no deprecation notice. However, I agree that the "map-with-lambda" pattern is better implemented with a comprehension or generator.

Ignacio Vazquez-Abrams Over a year ago

@Greg: But it's no longer the same map().

Greg Hewgill Over a year ago

That's a pretty fine point, since either one would work equally well in the OP's code.

Ignacio Vazquez-Abrams Over a year ago

That's not a list comprehension, it's a generator expression. It trades the initial cost of generating the list for a per-access cost of generating each element.

|

user694163 · Accepted Answer · 2012-01-04 06:11:06Z

0

why not use list expression?

",".join([ date.strftime("%d/%m/%Y") for date in range])

yes, map is deprecated, this is in the official documentation, because list expression is better optimized.

answered Jan 4, 2012 at 6:11

user694163

5772 gold badges5 silver badges10 bronze badges

2 Comments

Alex L Over a year ago

It doesn't say deprecated on the page I'm looking at here. Could you show me where you see deprecated?

user694163 Over a year ago

OK, i think "deprecated" maybe a little bit too much, sorry for that, "not encouraged" is better for the performance issue. I guess it comes out from link

Collectives™ on Stack Overflow

Format comma seperated list of dates in python

2 Answers 2

6 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related