Many thanks for all these suggestions! here is a short proof that you guys are absolutely right and my solution is pretty inefficient.
One of your ways: $ python /[long_path]/timeit.py 'a=[(1,2,3),(4,5,6)];b=(7,8);[x+(y,) for x,y in zip(a,b)]' 1000000 loops, best of 3: 1.44 usec per loop And my way: $ python /[long_path]/timeit.py 'a=[(1,2,3), (4,5,6)];b=[7,8];map(tuple, map(lambda x: x + [b.pop(0)] , map(list, a)))' 100000 loops, best of 3: 5.33 usec per loop I really appreciate your solutions but they bring me to a new question: Why is my solution so inefficient? The same operation without the list/tuple conversion $ python /[long_path]/timeit.py 'a=[[1,2,3], [4,5,6]];b=[7,8];map(lambda x: x + [b.pop(0)] , a)' 100000 loops, best of 3: 3.36 usec per loop is still horrible slow. Could anybody explain me what it makes so slow? Is it the map() function or maybe the lambda construct? Greetings, Daniel -- http://mail.python.org/mailman/listinfo/python-list
