How to concatenate two integers in Python?

Question

How do I concatenate two integer numbers (for example: 10 and 20) in Python to get a returned value of 1020?

Answer 1

To concatenate a list of integers

int(''.join(map(str, my_list)))

Answer 2

Using this function you can concatenate as many numbers as you want

def concat(*args):
    string = ''
    for each in args:
        string += str(each) 
    return int(string)

For example concat(20, 10, 30) will return 201030 an an integer

OR

You can use the one line program

int(''.join(str(x) for x in (20,10,30)))

This will also return 201030.

Answer 3

def concatenate_int(x, y):

  try:
     a = floor(log10(y))
  except ValueError:
     a = 0
  return int(x * 10 ** (1 + a) + y)


def concatenate(*l):
  j = 0
  for i in list(*l):
     j = concatenate_int(j, i)
  return j

Answer 4

using old-style string formatting:

>>> x = 10
>>> y = 20
>>> z = int('%d%d' % (x, y))
>>> print z
1020

Answer 5

Of course the 'correct' answer would be Konstantin's answer. But if you still want to know how to do it without using string casts, just with math:

import math

def numcat(a,b):
    return int(math.pow(10,(int(math.log(b,10)) + 1)) * a + b)

>> numcat(10, 20)
>> 1020

Answer 6

A rough but working implementation:

i1,i2 = 10,20
num = int('%i%i' % (i1,i2))

Basically, you just merge two numbers into one string and then cast that back to int.