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Doc fixes. Remove overbroad, redundant warnings. Fixup example code.

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Raymond Hettinger 2009-02-04 11:59:49 +00:00
parent e17570d7fd
commit 1e884d9f67
1 changed files with 9 additions and 27 deletions
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36
Doc/library/operator.rst
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@ -298,6 +298,15 @@ Operations which work with sequences include:
This function is removed in Python 3.0. Use :func:`setitem` with a slice This function is removed in Python 3.0. Use :func:`setitem` with a slice
index. index.
Example use of operator functions::
>>> # Elementwise multiplication
>>> map(mul, [0, 1, 2, 3], [10, 20, 30, 40])
[0, 20, 60, 120]
>>> # Dot product
>>> sum(map(mul, [0, 1, 2, 3], [10, 20, 30, 40]))
200
Many operations have an "in-place" version. The following functions provide a Many operations have an "in-place" version. The following functions provide a
more primitive access to in-place operators than the usual syntax does; for more primitive access to in-place operators than the usual syntax does; for
@ -455,12 +464,6 @@ abstract base classes instead (see :mod:`collections` and
Returns true if the object *obj* supports the mapping interface. This is true for Returns true if the object *obj* supports the mapping interface. This is true for
dictionaries and all instance objects defining :meth:`__getitem__`. dictionaries and all instance objects defining :meth:`__getitem__`.
.. warning::
There is no reliable way to test if an instance supports the complete mapping
protocol since the interface itself is ill-defined. This makes this test less
useful than it otherwise might be.
.. function:: isNumberType(obj) .. function:: isNumberType(obj)
@ -470,12 +473,6 @@ abstract base classes instead (see :mod:`collections` and
Returns true if the object *obj* represents a number. This is true for all Returns true if the object *obj* represents a number. This is true for all
numeric types implemented in C. numeric types implemented in C.
.. warning::
There is no reliable way to test if an instance supports the complete numeric
interface since the interface itself is ill-defined. This makes this test less
useful than it otherwise might be.
.. function:: isSequenceType(obj) .. function:: isSequenceType(obj)
@ -486,21 +483,6 @@ abstract base classes instead (see :mod:`collections` and
for all objects which define sequence methods in C, and for all instance objects for all objects which define sequence methods in C, and for all instance objects
defining :meth:`__getitem__`. defining :meth:`__getitem__`.
.. warning::
There is no reliable way to test if an instance supports the complete sequence
interface since the interface itself is ill-defined. This makes this test less
useful than it otherwise might be.
Example: Build a dictionary that maps the ordinals from ``0`` to ``255`` to
their character equivalents.
>>> d = {}
>>> keys = range(256)
>>> vals = map(chr, keys)
>>> map(operator.setitem, [d]*len(keys), keys, vals) # doctest: +SKIP
.. XXX: find a better, readable, example
The :mod:`operator` module also defines tools for generalized attribute and item The :mod:`operator` module also defines tools for generalized attribute and item
lookups. These are useful for making fast field extractors as arguments for lookups. These are useful for making fast field extractors as arguments for