Connecting strings in a element without using double for loops Python

I need to generate every possible pairs in a list.
For example

list=['1','2','3']

The end result that I want to have is

new_list=['1-2','1-3','2-1','2-3','3-1','3-2']

In my case, 1-2 != 2-1.
Currently my code is

for x1 in b:
                for x2 in b:
                    if(x1==x2):
                        continue
                    else:
                        x3=x1+'-'+x2
                        new_list.append(x2)

As my actual data contains hundreds of list, is there any way to not use a double for loop?

>Solution :

Use itertools:

import itertools

#to include pairs with same element (i.e. 1-1, 2-2 and 3-3)
>>> ["-".join(pair) for pair in itertools.product(lst, lst)]
['1-1', '1-2', '1-3', '2-1', '2-2', '2-3', '3-1', '3-2', '3-3']

#to exclude pairs with the same element
>>> ["-".join(pair) for pair in itertools.permutations(lst, 2)]
['1-2', '1-3', '2-1', '2-3', '3-1', '3-2']