How to concisely get a string from a list of ints

Question

Python

There is a list of ints, you need to get a string like "1,3,5,12", but so that the code is concise (in one line).
a = [1, 3, 5, 12]
str_ =…

Answer 1

reduce(lambda x, y: '%s,%d' % (x, y), a)

Answer 2

str(a)[1:-1]

Answer 3

', '.join(map(str, a))

Answer 4

It is possible like this:",".join("%s" % str(item) for item in a)

Answer 5

reverse version, from string to list: [int(s) for s in str_.split(',')]

Answer 6

Apparently, all pythonists are here, I will write for js :)
> [1, 3, 5, 12].join()
"1,3,5,12"