How to print a list of strings in a specific manner?

Question

A list of strings is given to me and I have to print their elements in a specific manner.

suppose, L = ['RED', 'GREEN', 'BLUE']

and the output is supposed to be, RGBERLDEUEEN

Answer 1

A simple for loop will do the job.

L = ['RED', 'GREEN', 'BLUE']

s = ''
for i in range(max([len(x) for x in L])): #len of longest word in L
    for item in L:
        try:
            s += item[i] + ' '
        except IndexError:
            pass

print(s)

R G B E R L D E U E E N 

Answer 2

This uses some advanced concepts, but it's neat and tidy:

from itertools import zip_longest, chain
L = ['RED', 'GREEN', 'BLUE']
print(''.join(chain(*zip_longest(*L, fillvalue=''))))
# 'RGBERLDEUEEN'

To include spaces between the letters, you can do this instead:

' '.join(''.join(chain(*zip_longest(*L, fillvalue=''))))
# R G B E R L D E U E E N

Answer 3

Another solution using itertools :

from itertools import chain, zip_longest

l = ['RED', 'GREEN', 'BLUE']
print(*filter(bool, chain(*zip_longest(*l))))

Answer 4

This can probably be done with a nested while-for loop. Something like

length_of_longest_string = 0
for s in L:
    length_of_longest_string = max(len(s), length_of_longest_string)

i = 0
result_string = ""
while i < length_of_longest_string:
    for s in L:
        if i >= len(s):
            continue
        else:
            result_string += s[i] + " "
    i += 1

print(result_string)

where you just find the length of the longest string using the initial for loop.