Combining two lists to string [duplicate]

Question

Actually I'm trying to merge two lists to one string but keep them ordered meaning:

list1 = [1,2,3,4,5]
list2 = ["one", "two", "three", "four", "five"]

result = "1one2two3three4four5five"

(lists always have the same length but vary in contents)

At the moment I'm doing it this way:

result = ""
i = 0

for entry in list1:
    result += entry + list2[i]
    i += 1

I think there must be a more pythonic way to do this but I don't know it actually.

May someone of you can help me out on this.

Answer 1

list1 = [1,2,3,4,5]
list2 = ["one", "two", "three", "four", "five"]

print ''.join([str(a) + b for a,b in zip(list1,list2)])

1one2two3three4four5five

Answer 2

>>> import itertools
>>> ''.join(map(str, itertools.chain.from_iterable(zip(list1, list2))))
1one2two3three4four5five'

Explanation:

• zip(list1, list2) creates a list containing tuples of matching elements from the two lists:

  >>> zip(list1, list2)
  [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four'), (5, 'five')]
  

• itertools.chain.from_iterable() flattens that nested list:

  >>> list(chain.from_iterable(zip(list1, list2)))
  [1, 'one', 2, 'two', 3, 'three', 4, 'four', 5, 'five']
  

• Now we need to ensure that there are only strings, so we apply str() to all items using map()

• Eventually ''.join(...) merges the list items into a single string with no separator.

Answer 3

Using string formatting with str.join() and zip():

>>> list1 = [1,2,3,4,5]
>>> list2 = ["one", "two", "three", "four", "five"]

>>> "".join("{0}{1}".format(x,y) for x,y in zip(list1,list2))
'1one2two3three4four5five'

zip(list1,list2) returns something like this: [(1, 'one'), (2, 'two'), (3, 'three'), (4, 'four'), (5, 'five')].

Now for each item of this list we apply the string formatting and then join the whole generator expression using str.join().