how to get tuples from lists using list comprehension in python

Question

I have two lists and want to merges them into one list of tuples. I want to do it with list comprehension, I can get it working using map. but would be nice to know how list comprehension here will work. code here

>>> lst =  [1,2,3,4,5]
>>> lst2 = [6,7,8,9,10]
>>> tup = map(None,lst,lst2) # works fine
>>> tup
[(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)]
>>> l3 = [lst, lst2]
>>> l3
[[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
>>> zip(*l3) # works fine
[(1, 6), (2, 7), (3, 8), (4, 9), (5, 10)]

>>> [(i,j) for i in lst and for j in lst2] # does not work
  File "<stdin>", line 1
    [(i,j) for i in lst and for j in lst2]
                              ^
SyntaxError: invalid syntax
>>> 

I have written comments where it works and where it does not. How can a two for-loop be coupled in list comprehension

Answer 1

Think about list comprehensions as loops. How can you write 2 not nested loops?

You can do this with somewhat wierd list comprehension:

[(x, lst2[i]) for i, x in enumerate(lst)]

or

[(lst[i], lst2[i]) for i in xrange(len(lst))]

But actually, it's better to use zip.