a few updates to the gloassary with regards to __future__ and division

This commit is contained in:
Benjamin Peterson 2008-11-21 00:25:02 +00:00
parent 58425d3103
commit 2d71822fdb
1 changed files with 12 additions and 27 deletions

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@ -74,10 +74,7 @@ Glossary
``int(3.15)`` converts the floating point number to the integer ``3``, but ``int(3.15)`` converts the floating point number to the integer ``3``, but
in ``3+4.5``, each argument is of a different type (one int, one float), in ``3+4.5``, each argument is of a different type (one int, one float),
and both must be converted to the same type before they can be added or it and both must be converted to the same type before they can be added or it
will raise a ``TypeError``. Coercion between two operands can be will raise a ``TypeError``. Without coercion, all arguments of even
performed with the ``coerce`` builtin function; thus, ``3+4.5`` is
equivalent to calling ``operator.add(*coerce(3, 4.5))`` and results in
``operator.add(3.0, 4.5)``. Without coercion, all arguments of even
compatible types would have to be normalized to the same value by the compatible types would have to be normalized to the same value by the
programmer, e.g., ``float(3)+4.5`` rather than just ``3+4.5``. programmer, e.g., ``float(3)+4.5`` rather than just ``3+4.5``.
@ -180,6 +177,11 @@ Glossary
A module written in C or C++, using Python's C API to interact with the core and A module written in C or C++, using Python's C API to interact with the core and
with user code. with user code.
floor division
Mathematical division discarding any remainder. The floor division
operator is ``//``. For example, the expression ``11//4`` evaluates to
``2`` in contrast to the ``2.75`` returned by float true division.
function function
A series of statements which returns some value to a caller. It can also A series of statements which returns some value to a caller. It can also
be passed zero or more arguments which may be used in the execution of be passed zero or more arguments which may be used in the execution of
@ -187,16 +189,11 @@ Glossary
__future__ __future__
A pseudo module which programmers can use to enable new language features A pseudo module which programmers can use to enable new language features
which are not compatible with the current interpreter. For example, the which are not compatible with the current interpreter.
expression ``11/4`` currently evaluates to ``2``. If the module in which
it is executed had enabled *true division* by executing::
from __future__ import division By importing the :mod:`__future__` module and evaluating its variables,
you can see when a new feature was first added to the language and when it
the expression ``11/4`` would evaluate to ``2.75``. By importing the becomes the default::
:mod:`__future__` module and evaluating its variables, you can see when a
new feature was first added to the language and when it will become the
default::
>>> import __future__ >>> import __future__
>>> __future__.division >>> __future__.division
@ -271,18 +268,6 @@ Glossary
role in places where a constant hash value is needed, for example as a key role in places where a constant hash value is needed, for example as a key
in a dictionary. in a dictionary.
integer division
Mathematical division discarding any remainder. For example, the
expression ``11/4`` currently evaluates to ``2`` in contrast to the
``2.75`` returned by float division. Also called *floor division*. When
dividing two integers the outcome will always be another integer (having
the floor function applied to it). However, if the operands types are
different, one of them will be converted to the other's type. For
example, an integer divided by a float will result in a float value,
possibly with a decimal fraction. Integer division can be forced by using
the ``//`` operator instead of the ``/`` operator. See also
:term:`__future__`.
interactive interactive
Python has an interactive interpreter which means you can enter Python has an interactive interpreter which means you can enter
statements and expressions at the interpreter prompt, immediately statements and expressions at the interpreter prompt, immediately