foo
bar

mylist = [
    'hello',
    'world'
]

def _gen():
    for x in mylist:
        with open('/tmp/list') as fh:
            yield('-'.join([x, next(fh)]))


for i in _gen():
    print(i)

hello-foo
world-foo

hello-foo
hello-bar
world-foo
world-bar

for x in mylist:
    with open('/tmp/list') as fh:
        for line in fh:
            yield '-'.join([x, line.strip()])