Writing a string.ishex function

[Christian Heimes]

Iain King wrote:
> better would be:
> def ishex(s):
>     for c in s:
>         if c not in string.hexdigits:
>             return False
>     return True

Even more elegant and probably a faster solutions:

---
from string import hexdigits
hexdigits = frozenset(hexdigits)

def ishex(s):
    return set(s).issubset(hexdigits)
---

If you are also interested in the integer value of a hex string:

---
def gethex(s):
    try:
        return int(s, 16)
    except ValueError:
        return None
---

Check for "gethex(s) is not None" to see if s is a hex string.

Christian