Question

I need to append/format a URL with a list of ids for an API call.

However, when I put the list at the end of the API:

https://api.twitter.com/1.1/users/lookup.json?user_id=%s'%a

I just get an empty string as a response.

I have tried turning the list into a string and removing the square brackets, doing:

a = str(followers['ids'])[1:-1]

but I still get the same problem. I’m assuming that it’s being caused by the single quote at the start.

I have tried removing the apostrophe from the string doing:

a.replace("'", "")

and now I have run out of ideas.

Answer 1

I have tried removing the apostrophe from the string doing …

You can remove apostrophe from a string using s = s.replace("'", ""). .replace() returns a new string but does not change the orginal string so you’ll to store the returned string.

>>> string = "he's a jolly good fellow"
>>> string = string.replace("'", "") 
>>> string
'hes a jolly good fellow'

But I don’t think that’s not your problem.

The ids need to be comma separated, so you’ll probably want to use a .join() to create the string from your list of ids. Example:

>>> ids = ["1", "23", "123"]
>>> ",".join(ids)
'1,23,123'

In your case, assuming followers['ids'] contain a list of id as strings, you can generate your URL using:

ids = ",".join(followers['ids'])  # generate string of ids (comma separated)
url = "https://api.twitter.com/1.1/users/lookup.json?user_id=%s" % ids

If followers['ids'] is a list of integers instead of string, then there’s a little more work to do since .join() works only with a sequence of strings. Here’s one way to convert those integers to string on the fly (using a generator expression):

ids = ",".join(str(id) for id in followers['ids'])