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Update the documentation for the isinstance() function to reflect recent

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changes in the implementation.
Indented all descriptions consistently.
This commit is contained in:
Fred Drake 2001-10-09 19:31:08 +00:00
parent fee435af8b
commit e0063d20a7
1 changed files with 218 additions and 213 deletions
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431
Doc/lib/libfuncs.tex
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@ -7,44 +7,42 @@ are always available. They are listed here in alphabetical order.
\setindexsubitem{(built-in function)} \setindexsubitem{(built-in function)}
\begin{funcdesc}{__import__}{name\optional{, globals\optional{, locals\optional{, fromlist}}}} \begin{funcdesc}{__import__}{name\optional{, globals\optional{, locals\optional{, fromlist}}}}
This function is invoked by the This function is invoked by the \keyword{import}\stindex{import}
\keyword{import}\stindex{import} statement. It mainly statement. It mainly exists so that you can replace it with another
exists so that you can replace it with another function that has a function that has a compatible interface, in order to change the
compatible interface, in order to change the semantics of the semantics of the \keyword{import} statement. For examples of why
\keyword{import} statement. For examples of why and how you would do and how you would do this, see the standard library modules
this, see the standard library modules \module{ihooks}\refstmodindex{ihooks} and
\module{ihooks}\refstmodindex{ihooks} and \refmodule{rexec}\refstmodindex{rexec}. See also the built-in
\refmodule{rexec}\refstmodindex{rexec}. See also the built-in module module \refmodule{imp}\refbimodindex{imp}, which defines some useful
\refmodule{imp}\refbimodindex{imp}, which defines some useful operations out of which you can build your own
operations out of which you can build your own \function{__import__()} function.
\function{__import__()} function.
For example, the statement \samp{import spam} results in the For example, the statement \samp{import spam} results in the
following call: following call: \code{__import__('spam',} \code{globals(),}
\code{__import__('spam',} \code{globals(),} \code{locals(), [])}; \code{locals(), [])}; the statement \samp{from spam.ham import eggs}
the statement \samp{from spam.ham import eggs} results results in \samp{__import__('spam.ham', globals(), locals(),
in \samp{__import__('spam.ham', globals(), locals(), ['eggs'])}. ['eggs'])}. Note that even though \code{locals()} and
Note that even though \code{locals()} and \code{['eggs']} are passed \code{['eggs']} are passed in as arguments, the
in as arguments, the \function{__import__()} function does not set the \function{__import__()} function does not set the local variable
local variable named \code{eggs}; this is done by subsequent code that named \code{eggs}; this is done by subsequent code that is generated
is generated for the import statement. (In fact, the standard for the import statement. (In fact, the standard implementation
implementation does not use its \var{locals} argument at all, and uses does not use its \var{locals} argument at all, and uses its
its \var{globals} only to determine the package context of the \var{globals} only to determine the package context of the
\keyword{import} statement.) \keyword{import} statement.)
When the \var{name} variable is of the form \code{package.module}, When the \var{name} variable is of the form \code{package.module},
normally, the top-level package (the name up till the first dot) is normally, the top-level package (the name up till the first dot) is
returned, \emph{not} the module named by \var{name}. However, when a returned, \emph{not} the module named by \var{name}. However, when
non-empty \var{fromlist} argument is given, the module named by a non-empty \var{fromlist} argument is given, the module named by
\var{name} is returned. This is done for compatibility with the \var{name} is returned. This is done for compatibility with the
bytecode generated for the different kinds of import statement; when bytecode generated for the different kinds of import statement; when
using \samp{import spam.ham.eggs}, the top-level package \code{spam} using \samp{import spam.ham.eggs}, the top-level package \code{spam}
must be placed in the importing namespace, but when using \samp{from must be placed in the importing namespace, but when using \samp{from
spam.ham import eggs}, the \code{spam.ham} subpackage must be used to spam.ham import eggs}, the \code{spam.ham} subpackage must be used
find the \code{eggs} variable. to find the \code{eggs} variable. As a workaround for this
As a workaround for this behavior, use \function{getattr()} to extract behavior, use \function{getattr()} to extract the desired
the desired components. For example, you could define the following components. For example, you could define the following helper:
helper:
\begin{verbatim} \begin{verbatim}
import string import string
@ -56,7 +54,6 @@ def my_import(name):
mod = getattr(mod, comp) mod = getattr(mod, comp)
return mod return mod
\end{verbatim} \end{verbatim}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{abs}{x} \begin{funcdesc}{abs}{x}
@ -66,35 +63,36 @@ def my_import(name):
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{apply}{function, args\optional{, keywords}} \begin{funcdesc}{apply}{function, args\optional{, keywords}}
The \var{function} argument must be a callable object (a user-defined or The \var{function} argument must be a callable object (a
built-in function or method, or a class object) and the \var{args} user-defined or built-in function or method, or a class object) and
argument must be a sequence (if it is not a tuple, the sequence is the \var{args} argument must be a sequence (if it is not a tuple,
first converted to a tuple). The \var{function} is called with the sequence is first converted to a tuple). The \var{function} is
\var{args} as the argument list; the number of arguments is the the length called with \var{args} as the argument list; the number of arguments
of the tuple. (This is different from just calling is the the length of the tuple. (This is different from just
\code{\var{func}(\var{args})}, since in that case there is always calling \code{\var{func}(\var{args})}, since in that case there is
exactly one argument.) always exactly one argument.)
If the optional \var{keywords} argument is present, it must be a If the optional \var{keywords} argument is present, it must be a
dictionary whose keys are strings. It specifies keyword arguments to dictionary whose keys are strings. It specifies keyword arguments
be added to the end of the the argument list. to be added to the end of the the argument list.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{buffer}{object\optional{, offset\optional{, size}}} \begin{funcdesc}{buffer}{object\optional{, offset\optional{, size}}}
The \var{object} argument must be an object that supports the The \var{object} argument must be an object that supports the buffer
buffer call interface (such as strings, arrays, and buffers). A new call interface (such as strings, arrays, and buffers). A new buffer
buffer object will be created which references the \var{object} argument. object will be created which references the \var{object} argument.
The buffer object will be a slice from the beginning of \var{object} The buffer object will be a slice from the beginning of \var{object}
(or from the specified \var{offset}). The slice will extend to the (or from the specified \var{offset}). The slice will extend to the
end of \var{object} (or will have a length given by the \var{size} end of \var{object} (or will have a length given by the \var{size}
argument). argument).
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{callable}{object} \begin{funcdesc}{callable}{object}
Return true if the \var{object} argument appears callable, false if Return true if the \var{object} argument appears callable, false if
not. If this returns true, it is still possible that a call fails, not. If this returns true, it is still possible that a call fails,
but if it is false, calling \var{object} will never succeed. Note but if it is false, calling \var{object} will never succeed. Note
that classes are callable (calling a class returns a new instance); that classes are callable (calling a class returns a new instance);
class instances are callable if they have a \method{__call__()} method. class instances are callable if they have a \method{__call__()}
method.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{chr}{i} \begin{funcdesc}{chr}{i}
@ -258,12 +256,12 @@ class instances are callable if they have a \method{__call__()} method.
environment where \function{execfile()} is called. The return value is environment where \function{execfile()} is called. The return value is
\code{None}. \code{None}.
\strong{Warning:} The default \var{locals} act as described for function \warning{The default \var{locals} act as described for function
\function{locals()} below: modifications to the default \var{locals} \function{locals()} below: modifications to the default \var{locals}
dictionary should not be attempted. Pass an explicit \var{locals} dictionary should not be attempted. Pass an explicit \var{locals}
dictionary if you need to see effects of the code on \var{locals} after dictionary if you need to see effects of the code on \var{locals} after
function \function{execfile()} returns. \function{execfile()} cannot function \function{execfile()} returns. \function{execfile()} cannot
be used reliably to modify a function's locals. be used reliably to modify a function's locals.}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{file}{filename\optional{, mode\optional{, bufsize}}} \begin{funcdesc}{file}{filename\optional{, mode\optional{, bufsize}}}
@ -328,11 +326,11 @@ class instances are callable if they have a \method{__call__()} method.
number with the same value (within Python's floating point number with the same value (within Python's floating point
precision) is returned. precision) is returned.
\strong{Note:} When passing in a string, values for NaN\index{NaN} \note{When passing in a string, values for NaN\index{NaN}
and Infinity\index{Infinity} may be returned, depending on the and Infinity\index{Infinity} may be returned, depending on the
underlying C library. The specific set of strings accepted which underlying C library. The specific set of strings accepted which
cause these values to be returned depends entirely on the C library cause these values to be returned depends entirely on the C library
and is known to vary. and is known to vary.}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{getattr}{object, name\optional{, default}} \begin{funcdesc}{getattr}{object, name\optional{, default}}
@ -345,10 +343,10 @@ class instances are callable if they have a \method{__call__()} method.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{globals}{} \begin{funcdesc}{globals}{}
Return a dictionary representing the current global symbol table. Return a dictionary representing the current global symbol table.
This is always the dictionary of the current module (inside a This is always the dictionary of the current module (inside a
function or method, this is the module where it is defined, not the function or method, this is the module where it is defined, not the
module from which it is called). module from which it is called).
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{hasattr}{object, name} \begin{funcdesc}{hasattr}{object, name}
@ -386,14 +384,14 @@ module from which it is called).
\begin{funcdesc}{input}{\optional{prompt}} \begin{funcdesc}{input}{\optional{prompt}}
Equivalent to \code{eval(raw_input(\var{prompt}))}. Equivalent to \code{eval(raw_input(\var{prompt}))}.
\strong{Warning:} This function is not safe from user errors! It \warning{This function is not safe from user errors! It
expects a valid Python expression as input; if the input is not expects a valid Python expression as input; if the input is not
syntactically valid, a \exception{SyntaxError} will be raised. syntactically valid, a \exception{SyntaxError} will be raised.
Other exceptions may be raised if there is an error during Other exceptions may be raised if there is an error during
evaluation. (On the other hand, sometimes this is exactly what you evaluation. (On the other hand, sometimes this is exactly what you
need when writing a quick script for expert use.) need when writing a quick script for expert use.)}
If the \module{readline} module was loaded, then If the \refmodule{readline} module was loaded, then
\function{input()} will use it to provide elaborate line editing and \function{input()} will use it to provide elaborate line editing and
history features. history features.
@ -430,21 +428,26 @@ module from which it is called).
garbage collected). garbage collected).
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{isinstance}{object, class} \begin{funcdesc}{isinstance}{object, classinfo}
Return true if the \var{object} argument is an instance of the Return true if the \var{object} argument is an instance of the
\var{class} argument, or of a (direct or indirect) subclass thereof. \var{classinfo} argument, or of a (direct or indirect) subclass
Also return true if \var{class} is a type object and \var{object} is thereof. Also return true if \var{classinfo} is a type object and
an object of that type. If \var{object} is not a class instance or a \var{object} is an object of that type. If \var{object} is not a
object of the given type, the function always returns false. If class instance or a object of the given type, the function always
\var{class} is neither a class object nor a type object, a returns false. If \var{classinfo} is neither a class object nor a
\exception{TypeError} exception is raised. type object, it may be a tuple of class or type objects, or may
recursively contain other such tuples (other sequence types are not
accepted). If \var{classinfo} is not a class, type, or tuple of
classes, types, and such tuples, a \exception{TypeError} exception
is raised.
\versionchanged[Support for a tuple of type information was added]{2.2}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{issubclass}{class1, class2} \begin{funcdesc}{issubclass}{class1, class2}
Return true if \var{class1} is a subclass (direct or indirect) of Return true if \var{class1} is a subclass (direct or indirect) of
\var{class2}. A class is considered a subclass of itself. If either \var{class2}. A class is considered a subclass of itself. If
argument is not a class object, a \exception{TypeError} exception is either argument is not a class object, a \exception{TypeError}
raised. exception is raised.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{iter}{o\optional{, sentinel}} \begin{funcdesc}{iter}{o\optional{, sentinel}}
@ -480,10 +483,10 @@ raised.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{locals}{} \begin{funcdesc}{locals}{}
Return a dictionary representing the current local symbol table. Return a dictionary representing the current local symbol table.
\strong{Warning:} The contents of this dictionary should not be \warning{The contents of this dictionary should not be modified;
modified; changes may not affect the values of local variables used by changes may not affect the values of local variables used by the
the interpreter. interpreter.}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{long}{x\optional{, radix}} \begin{funcdesc}{long}{x\optional{, radix}}
@ -612,74 +615,75 @@ the interpreter.
"Monty Python's Flying Circus" "Monty Python's Flying Circus"
\end{verbatim} \end{verbatim}
If the \module{readline} module was loaded, then If the \refmodule{readline} module was loaded, then
\function{raw_input()} will use it to provide elaborate \function{raw_input()} will use it to provide elaborate
line editing and history features. line editing and history features.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{reduce}{function, sequence\optional{, initializer}} \begin{funcdesc}{reduce}{function, sequence\optional{, initializer}}
Apply \var{function} of two arguments cumulatively to the items of Apply \var{function} of two arguments cumulatively to the items of
\var{sequence}, from left to right, so as to reduce the sequence to \var{sequence}, from left to right, so as to reduce the sequence to
a single value. For example, a single value. For example,
\code{reduce(lambda x, y: x+y, [1, 2, 3, 4, 5])} calculates \code{reduce(lambda x, y: x+y, [1, 2, 3, 4, 5])} calculates
\code{((((1+2)+3)+4)+5)}. \code{((((1+2)+3)+4)+5)}.
If the optional \var{initializer} is present, it is placed before the If the optional \var{initializer} is present, it is placed before
items of the sequence in the calculation, and serves as a default when the items of the sequence in the calculation, and serves as a
the sequence is empty. default when the sequence is empty.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{reload}{module} \begin{funcdesc}{reload}{module}
Re-parse and re-initialize an already imported \var{module}. The Re-parse and re-initialize an already imported \var{module}. The
argument must be a module object, so it must have been successfully argument must be a module object, so it must have been successfully
imported before. This is useful if you have edited the module source imported before. This is useful if you have edited the module
file using an external editor and want to try out the new version source file using an external editor and want to try out the new
without leaving the Python interpreter. The return value is the version without leaving the Python interpreter. The return value is
module object (the same as the \var{module} argument). the module object (the same as the \var{module} argument).
There are a number of caveats: There are a number of caveats:
If a module is syntactically correct but its initialization fails, the If a module is syntactically correct but its initialization fails,
first \keyword{import} statement for it does not bind its name locally, the first \keyword{import} statement for it does not bind its name
but does store a (partially initialized) module object in locally, but does store a (partially initialized) module object in
\code{sys.modules}. To reload the module you must first \code{sys.modules}. To reload the module you must first
\keyword{import} it again (this will bind the name to the partially \keyword{import} it again (this will bind the name to the partially
initialized module object) before you can \function{reload()} it. initialized module object) before you can \function{reload()} it.
When a module is reloaded, its dictionary (containing the module's When a module is reloaded, its dictionary (containing the module's
global variables) is retained. Redefinitions of names will override global variables) is retained. Redefinitions of names will override
the old definitions, so this is generally not a problem. If the new the old definitions, so this is generally not a problem. If the new
version of a module does not define a name that was defined by the old version of a module does not define a name that was defined by the
version, the old definition remains. This feature can be used to the old version, the old definition remains. This feature can be used
module's advantage if it maintains a global table or cache of objects to the module's advantage if it maintains a global table or cache of
--- with a \keyword{try} statement it can test for the table's presence objects --- with a \keyword{try} statement it can test for the
and skip its initialization if desired. table's presence and skip its initialization if desired.
It is legal though generally not very useful to reload built-in or It is legal though generally not very useful to reload built-in or
dynamically loaded modules, except for \module{sys}, \module{__main__} dynamically loaded modules, except for \refmodule{sys},
and \module{__builtin__}. In many cases, however, extension \refmodule[main]{__main__} and \refmodule[builtin]{__builtin__}. In
modules are not designed to be initialized more than once, and may many cases, however, extension modules are not designed to be
fail in arbitrary ways when reloaded. initialized more than once, and may fail in arbitrary ways when
reloaded.
If a module imports objects from another module using \keyword{from} If a module imports objects from another module using \keyword{from}
\ldots{} \keyword{import} \ldots{}, calling \function{reload()} for \ldots{} \keyword{import} \ldots{}, calling \function{reload()} for
the other module does not redefine the objects imported from it --- the other module does not redefine the objects imported from it ---
one way around this is to re-execute the \keyword{from} statement, one way around this is to re-execute the \keyword{from} statement,
another is to use \keyword{import} and qualified names another is to use \keyword{import} and qualified names
(\var{module}.\var{name}) instead. (\var{module}.\var{name}) instead.
If a module instantiates instances of a class, reloading the module If a module instantiates instances of a class, reloading the module
that defines the class does not affect the method definitions of the that defines the class does not affect the method definitions of the
instances --- they continue to use the old class definition. The same instances --- they continue to use the old class definition. The
is true for derived classes. same is true for derived classes.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{repr}{object} \begin{funcdesc}{repr}{object}
Return a string containing a printable representation of an object. Return a string containing a printable representation of an object.
This is the same value yielded by conversions (reverse quotes). This is the same value yielded by conversions (reverse quotes).
It is sometimes useful to be able to access this operation as an It is sometimes useful to be able to access this operation as an
ordinary function. For many types, this function makes an attempt ordinary function. For many types, this function makes an attempt
to return a string that would yield an object with the same value to return a string that would yield an object with the same value
when passed to \function{eval()}. when passed to \function{eval()}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{round}{x\optional{, n}} \begin{funcdesc}{round}{x\optional{, n}}
@ -701,42 +705,43 @@ when passed to \function{eval()}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{slice}{\optional{start,} stop\optional{, step}} \begin{funcdesc}{slice}{\optional{start,} stop\optional{, step}}
Return a slice object representing the set of indices specified by Return a slice object representing the set of indices specified by
\code{range(\var{start}, \var{stop}, \var{step})}. The \var{start} \code{range(\var{start}, \var{stop}, \var{step})}. The \var{start}
and \var{step} arguments default to None. Slice objects have and \var{step} arguments default to None. Slice objects have
read-only data attributes \member{start}, \member{stop} and \member{step} read-only data attributes \member{start}, \member{stop} and
which merely return the argument values (or their default). They have \member{step} which merely return the argument values (or their
no other explicit functionality; however they are used by Numerical default). They have no other explicit functionality; however they
Python\index{Numerical Python} and other third party extensions. are used by Numerical Python\index{Numerical Python} and other third
Slice objects are also generated when extended indexing syntax is party extensions. Slice objects are also generated when extended
used. For example: \samp{a[start:stop:step]} or \samp{a[start:stop, i]}. indexing syntax is used. For example: \samp{a[start:stop:step]} or
\samp{a[start:stop, i]}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{str}{object} \begin{funcdesc}{str}{object}
Return a string containing a nicely printable representation of an Return a string containing a nicely printable representation of an
object. For strings, this returns the string itself. The difference object. For strings, this returns the string itself. The
with \code{repr(\var{object})} is that \code{str(\var{object})} does not difference with \code{repr(\var{object})} is that
always attempt to return a string that is acceptable to \function{eval()}; \code{str(\var{object})} does not always attempt to return a string
its goal is to return a printable string. that is acceptable to \function{eval()}; its goal is to return a
printable string.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{tuple}{sequence} \begin{funcdesc}{tuple}{sequence}
Return a tuple whose items are the same and in the same order as Return a tuple whose items are the same and in the same order as
\var{sequence}'s items. \var{sequence} may be a sequence, a \var{sequence}'s items. \var{sequence} may be a sequence, a
container that supports iteration, or an iterator object. container that supports iteration, or an iterator object.
If \var{sequence} is already a tuple, it If \var{sequence} is already a tuple, it
is returned unchanged. For instance, \code{tuple('abc')} returns is returned unchanged. For instance, \code{tuple('abc')} returns
returns \code{('a', 'b', 'c')} and \code{tuple([1, 2, 3])} returns returns \code{('a', 'b', 'c')} and \code{tuple([1, 2, 3])} returns
\code{(1, 2, 3)}. \code{(1, 2, 3)}.
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{type}{object} \begin{funcdesc}{type}{object}
Return the type of an \var{object}. The return value is a type Return the type of an \var{object}. The return value is a
object. The standard module \module{types} defines names for all type\obindex{type} object. The standard module
built-in types. \module{types}\refstmodindex{types} defines names for all built-in
\refstmodindex{types} types.
\obindex{type} For instance:
For instance:
\begin{verbatim} \begin{verbatim}
>>> import types >>> import types
@ -745,62 +750,62 @@ For instance:
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{unichr}{i} \begin{funcdesc}{unichr}{i}
Return the Unicode string of one character whose Unicode code is the Return the Unicode string of one character whose Unicode code is the
integer \var{i}. For example, \code{unichr(97)} returns the string integer \var{i}. For example, \code{unichr(97)} returns the string
\code{u'a'}. This is the inverse of \function{ord()} for Unicode \code{u'a'}. This is the inverse of \function{ord()} for Unicode
strings. The argument must be in the range [0..65535], inclusive. strings. The argument must be in the range [0..65535], inclusive.
\exception{ValueError} is raised otherwise. \exception{ValueError} is raised otherwise.
\versionadded{2.0} \versionadded{2.0}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{unicode}{string\optional{, encoding\optional{, errors}}} \begin{funcdesc}{unicode}{string\optional{, encoding\optional{, errors}}}
Create a Unicode string from an 8-bit string \var{string} using the Create a Unicode string from an 8-bit string \var{string} using the
codec for \var{encoding}. The \var{encoding} parameter is a string codec for \var{encoding}. The \var{encoding} parameter is a string
giving the name of an encoding. Error handling is done according to giving the name of an encoding. Error handling is done according to
\var{errors}; this specifies the treatment of characters which are \var{errors}; this specifies the treatment of characters which are
invalid in the input encoding. If \var{errors} is \code{'strict'} invalid in the input encoding. If \var{errors} is \code{'strict'}
(the default), a \exception{ValueError} is raised on errors, while a (the default), a \exception{ValueError} is raised on errors, while a
value of \code{'ignore'} causes errors to be silently ignored, and a value of \code{'ignore'} causes errors to be silently ignored, and a
value of \code{'replace'} causes the official Unicode replacement value of \code{'replace'} causes the official Unicode replacement
character, \code{U+FFFD}, to be used to replace input characters which character, \code{U+FFFD}, to be used to replace input characters
cannot be decoded. The default behavior is to decode UTF-8 in strict which cannot be decoded. The default behavior is to decode UTF-8 in
mode, meaning that encoding errors raise \exception{ValueError}. See strict mode, meaning that encoding errors raise
also the \refmodule{codecs} module. \exception{ValueError}. See also the \refmodule{codecs} module.
\versionadded{2.0} \versionadded{2.0}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{vars}{\optional{object}} \begin{funcdesc}{vars}{\optional{object}}
Without arguments, return a dictionary corresponding to the current Without arguments, return a dictionary corresponding to the current
local symbol table. With a module, class or class instance object as local symbol table. With a module, class or class instance object
argument (or anything else that has a \member{__dict__} attribute), as argument (or anything else that has a \member{__dict__}
returns a dictionary corresponding to the object's symbol table. attribute), returns a dictionary corresponding to the object's
The returned dictionary should not be modified: the effects on the symbol table. The returned dictionary should not be modified: the
corresponding symbol table are undefined.\footnote{ effects on the corresponding symbol table are undefined.\footnote{
In the current implementation, local variable bindings cannot In the current implementation, local variable bindings cannot
normally be affected this way, but variables retrieved from normally be affected this way, but variables retrieved from
other scopes (such as modules) can be. This may change.} other scopes (such as modules) can be. This may change.}
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{xrange}{\optional{start,} stop\optional{, step}} \begin{funcdesc}{xrange}{\optional{start,} stop\optional{, step}}
This function is very similar to \function{range()}, but returns an This function is very similar to \function{range()}, but returns an
``xrange object'' instead of a list. This is an opaque sequence type ``xrange object'' instead of a list. This is an opaque sequence
which yields the same values as the corresponding list, without type which yields the same values as the corresponding list, without
actually storing them all simultaneously. The advantage of actually storing them all simultaneously. The advantage of
\function{xrange()} over \function{range()} is minimal (since \function{xrange()} over \function{range()} is minimal (since
\function{xrange()} still has to create the values when asked for \function{xrange()} still has to create the values when asked for
them) except when a very large range is used on a memory-starved them) except when a very large range is used on a memory-starved
machine or when all of the range's elements are never used (such as machine or when all of the range's elements are never used (such as
when the loop is usually terminated with \keyword{break}). when the loop is usually terminated with \keyword{break}).
\end{funcdesc} \end{funcdesc}
\begin{funcdesc}{zip}{seq1, \moreargs} \begin{funcdesc}{zip}{seq1, \moreargs}
This function returns a list of tuples, where each tuple contains the This function returns a list of tuples, where each tuple contains
\var{i}-th element from each of the argument sequences. At least one the \var{i}-th element from each of the argument sequences. At
sequence is required, otherwise a \exception{TypeError} is raised. least one sequence is required, otherwise a \exception{TypeError} is
The returned list is truncated in length to the length of the shortest raised. The returned list is truncated in length to the length of
argument sequence. When there are multiple argument sequences which the shortest argument sequence. When there are multiple argument
are all of the same length, \function{zip()} is similar to sequences which are all of the same length, \function{zip()} is
\function{map()} with an initial argument of \code{None}. With a similar to \function{map()} with an initial argument of \code{None}.
single sequence argument, it returns a list of 1-tuples. With a single sequence argument, it returns a list of 1-tuples.
\versionadded{2.0} \versionadded{2.0}
\end{funcdesc} \end{funcdesc}