diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/release/1.10.0-notes.rst | 47 |
1 files changed, 43 insertions, 4 deletions
diff --git a/doc/release/1.10.0-notes.rst b/doc/release/1.10.0-notes.rst index cb78b4e71..50b1aa0b8 100644 --- a/doc/release/1.10.0-notes.rst +++ b/doc/release/1.10.0-notes.rst @@ -20,19 +20,23 @@ Highlights * Addition of `nanprod` to the set of nanfunctions. * Support for the '@' operator in Python 3.5. +Dropped Support: -Dropped Support -=============== * The polytemplate.py file has been removed. * The _dotblas module is no longer available. * The testcalcs.py file has been removed. +Future Changes: -Future Changes -============== +* In array comparisons like ``arr1 == arr2``, many corner cases + involving strings or structured dtypes that used to return scalars + now issue ``FutureWarning`` or ``DeprecationWarning``, and in the + future will be change to either perform elementwise comparisons or + raise an error. * The SafeEval class will be removed. * The alterdot and restoredot functions will be removed. +See below for more details on these changes. Compatibility notes =================== @@ -277,6 +281,41 @@ array is writeable. Deprecations ============ +Array comparisons involving strings or structured dtypes +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Normally, comparison operations on arrays perform elementwise +comparisons and return arrays of booleans. But in some corner cases, +especially involving strings are structured dtypes, NumPy has +historically returned a scalar instead. For example:: + + ### Current behaviour + + np.arange(2) == "foo" + # -> False + + np.arange(2) < "foo" + # -> True on Python 2, error on Python 3 + + np.ones(2, dtype="i4,i4") == np.ones(2, dtype="i4,i4,i4") + # -> False + +Continuing work started in 1.9, in 1.10 these comparisons will now +raise ``FutureWarning`` or ``DeprecationWarning``, and in the future +they will be modified to behave more consistently with other +comparison operations, e.g.:: + + ### Future behaviour + + np.arange(2) == "foo" + # -> array([False, False]) + + np.arange(2) < "foo" + # -> error, strings and numbers are not orderable + + np.ones(2, dtype="i4,i4") == np.ones(2, dtype="i4,i4,i4") + # -> [False, False] + SafeEval ~~~~~~~~ The SafeEval class in numpy/lib/utils.py is deprecated and will be removed |