How to concatenate two strings in python? [duplicate]

Question

def f1()
   in1="hello"
   in2="world"
   for i in in1:
       for j in in2:
           print(ij)
   
f1()

There two strings in1="hello" in2="world" expected output="hweolrllod"

Answer 1

You're almost there. Make the below changes in your code:

def f1():
    in1="hello"
    in2="world"
    for i,j in zip(in1, in2):
        print(i, j, sep='', end='')
            
   
f1()

If you don't want to use zip, try this:

def f1():
    in1="hello"
    in2="world"
    idx = 0
    for i in in1:
        for j in in2[idx:]:
            print(i, j, sep='', end='')
            idx += 1
            break

f1()

Output:

hweolrllod

Answer 2

You can zip to traverse the two strings together and unpack and join:

out = ''.join(x for pair in zip(in1, in2) for x in pair)

Output:

'hweolrllod'

Answer 3

Another way could be to use this:-

in1="hello"
in2="world"

print("".join(map("".join, zip(in1, in2))))

Answer 4

A faster version of @NewbieAF's answer:

"".join(a1+a2 for a1,a2 in zip(in1, in2))
#'hweolrllod'

Answer 5

This isn't the most efficient way but is easier to understand in terms of the logic needed.

def f1() -> None:
    in1 = "hello"
    in2 = "world"
    i = 0
    j = 0
    op = ""
    while i<len(in1) and j<len(in2):
        op = op + in1[i]
        op = op + in2[j]
        i = i + 1
        j = j + 1
    print(op)
    
f1()

Output

hweolrllod

Since you haven't mentioned the case where strings have different lengths, I have left that part.

Answer 6

in1 + in2 

Creates a new, concatenated, string.

But your question seems to indicate you want them only concatenated when printing. For that, do this:

print(in1, in2, sep="")