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| author | Raymond Hettinger <python@rcn.com> | 2003-07-16 19:40:23 (GMT) |
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| committer | Raymond Hettinger <python@rcn.com> | 2003-07-16 19:40:23 (GMT) |
| commit | 4d6e8fe5d13a313314550d7ebffafaf62dea1df2 (patch) | |
| tree | 49ef23772420662e3c4fe760710d4387d214270d /Doc/ref | |
| parent | 71adf7e9d8fb2aca563eeca806ea127409c82bb6 (diff) | |
| download | cpython-4d6e8fe5d13a313314550d7ebffafaf62dea1df2.zip cpython-4d6e8fe5d13a313314550d7ebffafaf62dea1df2.tar.gz cpython-4d6e8fe5d13a313314550d7ebffafaf62dea1df2.tar.bz2 | |
Clarify the lack of relationship between rich comparison operators.
Prompted by a discussion on comp.lang.python.
Diffstat (limited to 'Doc/ref')
| -rw-r--r-- | Doc/ref/ref3.tex | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Doc/ref/ref3.tex b/Doc/ref/ref3.tex index 785a995..68d87b4 100644 --- a/Doc/ref/ref3.tex +++ b/Doc/ref/ref3.tex @@ -1089,6 +1089,11 @@ used in a Boolean context, the return value should be interpretable as a Boolean value, else a \exception{TypeError} will be raised. By convention, \code{False} is used for false and \code{True} for true. +There are no implied relationships among the comparison operators. +The truth of {\var{x}==\var{y}} does not imply that \code{\var{x}!=\var{y}} +is false. Accordingly, when defining \method{__eq__}, one should also +define \method{__ne__} so that the operators will behave as expected. + There are no reflected (swapped-argument) versions of these methods (to be used when the left argument does not support the operation but the right argument does); rather, \method{__lt__()} and |