Question

Basically I’ve got this current url and this other key that I want to merge into a new url, but there are three different cases.

Suppose the current url is localhost:32401/A/B/foo

if key is bar then I want to return localhost:32401/A/B/bar

if key starts with a slash and is /A/bar then I want to return localhost:32401/A/bar

finally if key is its own independent url then I just want to return that key = http://foo.com/bar -> http://foo.com/bar

I assume there is a way to do at least the first two cases without manipulating the strings manually, but nothing jumped out at me immediately in the os.path module.

Answer 1

I assume there is a way to do at least the first two cases without manipulating the strings manually, but nothing jumped out at me immediately in the os.path module.

That’s because you want to use urllib.parse (for Python 3.x) or urlparse (for Python 2.x) instead.

I don’t have much experience with it, though, so here’s a snippet using str.split() and str.join().

urlparts = url.split('/')

if key.startswith('http://'):
    return key
elif key.startswith('/'):
    return '/'.join(urlparts[:2], key[1:])
else:
    urlparts[len(urlparts) - 1] = key
    return '/'.join(urlparts)