Since lambda x: print(x) is a syntax error in Python < 3, I’m assuming Python 3. That means map returns a generator, meaning to get map to actually call the function on every element of a list, you need to iterate through the resultant generator.

Fortunately, this can be done easily:

list(map(lambda x:print(x),primes))


Oh, and you can get rid of the lambda too, if you like:

list(map(print,primes))


But, at that point you are better off with letting print handle it:

print(*primes, sep='\n')


NOTE: I said earlier that '\n'.join would be a good idea. That is only true for a list of str’s.