I am trying to make a join of some lists within a list in python here is an example of what I am doing (the lists are much bigger in the real code):

```
import itertools

listenv = ["IN","VC","VS"]
listsize = ["U17-1","U17-2"]

listevnsize = list(itertools.product(listenv, listsize,))

print listevnsize
#This results in [('IN', 'U17-1'), ('IN', 'U17-2'), ('VC', 'U17-1'), ('VC', 'U17-2'), ('VS', 'U17-1'), ('VS', 'U17-2')]

```

What I want to do now is to combine the inner lists with a - for instance I would like the result to be:

```
[('IN-U17-1'), ('IN-U17-2'), ('VC-U17-1'), ('VC-U17-2'), ('VS-U17-1'), ('VS-U17-2')]

```

So in other words I would like to join the inner lists, but when I tried using:

```
listevnsizejoined = '-'.join(map(str,listevnsizezip))

```

As suggested in another question, this is joining all of the outer lists into one big string like this:

```
(('IN', 'U17-1'),)-(('IN', 'U17-2'),)-(('VC', 'U17-1'),)-(('VC', 'U17-2'),)-(('VS', 'U17-1'),)

```

FINAL SOLUTION:

```
import itertools

listenv = ["IN","VC","VS","VX","RH","HT","DP","AD","PT","PTRH","WP","WPRH","CYVX","HM"];
listsize = ["U17-1","U17-2"];
listseventeenGR = ["17P:3","17P:4","17P:5.5","17P:7","17P:10","17P:16","17P:22","17P:28","17P:40","17P:49","17P:55","17P:70","17P:100"]

listevnsize = list(itertools.product(listenv, listsize,))

listenvsizejoined = []

for x in listevnsize:
    listenvsizejoined.append('-'.join(i for i in x))

print listenvsizejoined

```

This is the final solution for combining two lists in all combinations, and then joining those inner lists with a dash.