diff options
Diffstat (limited to 'HACKING.rst')
| -rw-r--r-- | HACKING.rst | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/HACKING.rst b/HACKING.rst index 3f6a3ed..3cea316 100644 --- a/HACKING.rst +++ b/HACKING.rst @@ -26,16 +26,23 @@ General mylist = Foo().list() # OKAY, does not shadow built-in +- Use the "is not" operator when testing for unequal identities. Example:: -- Use the "not in" operator for collection membership evaluation. Example:: + if not X is Y: # BAD, intended behavior is ambiguous + pass + + if X is not Y: # OKAY, intuitive + pass + +- Use the "not in" operator for evaluating membership in a collection. Example:: - if not X in Y: # BAD, hard to understand + if not X in Y: # BAD, intended behavior is ambiguous pass if X not in Y: # OKAY, intuitive pass - if not (X in Y or X is Z): # OKAY, still better than all those 'not's + if not (X in Y or X in Z): # OKAY, still better than all those 'not's pass |