python - Joining elements of a list

Question

I have a list of tuples like:

data = [('a1', 'a2'), ('b1', 'b2')]

And I want to generate a string like this: "('a1', 'a2'), ('b1'. 'b2')"

If i do something like: ','.join(data), I get an error:

TypeError: sequence item 0: expected string, tuple found

If I want to do something in a single line without doing something like:

for elem in data:
  str += ',%s' % str(elem)

then is there a way?

Answer 1

Use a generator to cast the tuples to strings and then use join().

>>> ', '.join(str(d) for d in data)
"('a1', 'a2'), ('b1', 'b2')"