Part of SF patch #1513870 (the still relevant part) -- add reduce() to
functools, and adjust docs etc.
diff --git a/Doc/howto/doanddont.tex b/Doc/howto/doanddont.tex
index a105ca1..df3ca34 100644
--- a/Doc/howto/doanddont.tex
+++ b/Doc/howto/doanddont.tex
@@ -289,19 +289,7 @@
aware of for some reason: \function{min()} and \function{max()} can
find the minimum/maximum of any sequence with comparable semantics,
for example, yet many people write their own
-\function{max()}/\function{min()}. Another highly useful function is
-\function{reduce()}. A classical use of \function{reduce()}
-is something like
-
-\begin{verbatim}
-import sys, operator
-nums = map(float, sys.argv[1:])
-print reduce(operator.add, nums)/len(nums)
-\end{verbatim}
-
-This cute little script prints the average of all numbers given on the
-command line. The \function{reduce()} adds up all the numbers, and
-the rest is just some pre- and postprocessing.
+\function{max()}/\function{min()}.
On the same note, note that \function{float()}, \function{int()} and
\function{long()} all accept arguments of type string, and so are
diff --git a/Doc/lib/libfuncs.tex b/Doc/lib/libfuncs.tex
index 65b0bf5..c9e35b5 100644
--- a/Doc/lib/libfuncs.tex
+++ b/Doc/lib/libfuncs.tex
@@ -836,19 +836,6 @@
\end{verbatim}
\end{funcdesc}
-\begin{funcdesc}{reduce}{function, sequence\optional{, initializer}}
- Apply \var{function} of two arguments cumulatively to the items of
- \var{sequence}, from left to right, so as to reduce the sequence to
- a single value. For example, \code{reduce(lambda x, y: x+y, [1, 2,
- 3, 4, 5])} calculates \code{((((1+2)+3)+4)+5)}. The left argument,
- \var{x}, is the accumulated value and the right argument, \var{y},
- is the update value from the \var{sequence}. If the optional
- \var{initializer} is present, it is placed before the items of the
- sequence in the calculation, and serves as a default when the
- sequence is empty. If \var{initializer} is not given and
- \var{sequence} contains only one item, the first item is returned.
-\end{funcdesc}
-
\begin{funcdesc}{reload}{module}
Reload a previously imported \var{module}. The
argument must be a module object, so it must have been successfully
@@ -1058,8 +1045,6 @@
The \var{sequence}'s items are normally numbers, and are not allowed
to be strings. The fast, correct way to concatenate sequence of
strings is by calling \code{''.join(\var{sequence})}.
- Note that \code{sum(range(\var{n}), \var{m})} is equivalent to
- \code{reduce(operator.add, range(\var{n}), \var{m})}
\versionadded{2.3}
\end{funcdesc}
diff --git a/Doc/lib/libfunctools.tex b/Doc/lib/libfunctools.tex
index 33a6f52..034143a 100644
--- a/Doc/lib/libfunctools.tex
+++ b/Doc/lib/libfunctools.tex
@@ -51,6 +51,19 @@
\end{verbatim}
\end{funcdesc}
+\begin{funcdesc}{reduce}{function, sequence\optional{, initializer}}
+ Apply \var{function} of two arguments cumulatively to the items of
+ \var{sequence}, from left to right, so as to reduce the sequence to
+ a single value. For example, \code{reduce(lambda x, y: x+y, [1, 2,
+ 3, 4, 5])} calculates \code{((((1+2)+3)+4)+5)}. The left argument,
+ \var{x}, is the accumulated value and the right argument, \var{y},
+ is the update value from the \var{sequence}. If the optional
+ \var{initializer} is present, it is placed before the items of the
+ sequence in the calculation, and serves as a default when the
+ sequence is empty. If \var{initializer} is not given and
+ \var{sequence} contains only one item, the first item is returned.
+\end{funcdesc}
+
\begin{funcdesc}{update_wrapper}
{wrapper, wrapped\optional{, assigned}\optional{, updated}}
Update a wrapper function to look like the wrapped function. The optional
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex
index 1b08a8e..6f6fe6f 100644
--- a/Doc/tut/tut.tex
+++ b/Doc/tut/tut.tex
@@ -1893,8 +1893,8 @@
\subsection{Functional Programming Tools \label{functional}}
-There are three built-in functions that are very useful when used with
-lists: \function{filter()}, \function{map()}, and \function{reduce()}.
+There are two built-in functions that are very useful when used with
+lists: \function{filter()} and \function{map()}.
\samp{filter(\var{function}, \var{sequence})} returns a sequence
consisting of those items from the
@@ -1934,42 +1934,6 @@
>>> map(add, seq, seq)
[0, 2, 4, 6, 8, 10, 12, 14]
\end{verbatim}
-
-\samp{reduce(\var{function}, \var{sequence})} returns a single value
-constructed by calling the binary function \var{function} on the first two
-items of the sequence, then on the result and the next item, and so
-on. For example, to compute the sum of the numbers 1 through 10:
-
-\begin{verbatim}
->>> def add(x,y): return x+y
-...
->>> reduce(add, range(1, 11))
-55
-\end{verbatim}
-
-If there's only one item in the sequence, its value is returned; if
-the sequence is empty, an exception is raised.
-
-A third argument can be passed to indicate the starting value. In this
-case the starting value is returned for an empty sequence, and the
-function is first applied to the starting value and the first sequence
-item, then to the result and the next item, and so on. For example,
-
-\begin{verbatim}
->>> def sum(seq):
-... def add(x,y): return x+y
-... return reduce(add, seq, 0)
-...
->>> sum(range(1, 11))
-55
->>> sum([])
-0
-\end{verbatim}
-
-Don't use this example's definition of \function{sum()}: since summing
-numbers is such a common need, a built-in function
-\code{sum(\var{sequence})} is already provided, and works exactly like
-this.
\versionadded{2.3}
\subsection{List Comprehensions}
@@ -2739,7 +2703,7 @@
'id', 'int', 'intern', 'isinstance', 'issubclass', 'iter',
'len', 'license', 'list', 'locals', 'long', 'map', 'max', 'min',
'object', 'oct', 'open', 'ord', 'pow', 'property', 'quit', 'range',
- 'reduce', 'reload', 'repr', 'reversed', 'round', 'set',
+ 'reload', 'repr', 'reversed', 'round', 'set',
'setattr', 'slice', 'sorted', 'staticmethod', 'str', 'sum', 'super',
'tuple', 'type', 'unichr', 'unicode', 'vars', 'xrange', 'zip']
\end{verbatim}