python string formatting from list with arbitrary item

Question

I want to do a string formatting with a list as showed below:

(pseudocode)

down_url = [url1, url2, ..., urln]    
url = "download: %s" % down_url

Yes, the list down_url has arbitrary items, and I want to get all the items from it. The result I want is:

download: url1, url2, ..., urln

I hope you can understand what I have expressed. Thank you.

Tim Pietzcker · Accepted Answer · 2013-05-30 10:15:15Z

3

print("download: " + ", ".join(down_url))

Explanation:

"sep".join(iterable) joins all elements in iterable using the separator sep and returns a string. So for example:

>>> "".join(("a", "b", "c"))
'abc'
>>> ", ".join(("a", "b", "c"))
'a, b, c'

In case your iterable contains elements other than strings, you can force them to be mapped into strings before passing them to the .join() method:

>>> ", ".join(map(str, ("a", 2, "c")))
'a, 2, c'

answered May 30, 2013 at 10:15

Tim Pietzcker

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