[Python-checkins] python/dist/src/Doc/whatsnew whatsnew24.tex, 1.45, 1.46

rhettinger at users.sourceforge.net rhettinger at users.sourceforge.net
Wed May 19 18:30:28 EDT 2004


Update of /cvsroot/python/python/dist/src/Doc/whatsnew
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv18496

Modified Files:
	whatsnew24.tex 
Log Message:
Improved wording for generator expressions.

Index: whatsnew24.tex
===================================================================
RCS file: /cvsroot/python/python/dist/src/Doc/whatsnew/whatsnew24.tex,v
retrieving revision 1.45
retrieving revision 1.46
diff -C2 -d -r1.45 -r1.46
*** whatsnew24.tex	19 May 2004 19:45:19 -0000	1.45
--- whatsnew24.tex	19 May 2004 22:30:25 -0000	1.46
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*** 15,20 ****
  \tableofcontents
  
! This article explains the new features in Python 2.4.  No release date
! for Python 2.4 has been set; expect that this will happen mid-2004.
  
  While Python 2.3 was primarily a library development release, Python
--- 15,20 ----
  \tableofcontents
  
! This article explains the new features in Python 2.4.  The release
! date is expected to be around September 2004.
  
  While Python 2.3 was primarily a library development release, Python
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*** 92,101 ****
  \section{PEP 229: Generator Expressions}
  
! Generator expressions create in-line generators using a syntax similar
! to list comprehensions but with parenthesis instead of the surrounding
! brackets.
! 
! Genexps allow simple generators to be constructed without a separate function
! definition.  Writing:
         
  \begin{verbatim}
--- 92,101 ----
  \section{PEP 229: Generator Expressions}
  
! Now, simple generators can be coded succinctly as expressions using a syntax
! like list comprehensions but with parentheses instead of brackets.  These
! expressions are designed for situations where the generator is used right
! away by an enclosing function.  Generator expressions are more compact but
! less versatile than full generator definitions and the tend to be more memory
! friendly than equivalent list comprehensions.
         
  \begin{verbatim}
***************
*** 122,130 ****
  more readily than with list comprehensions.
  
! Generator expressions are intended to be used inside functions
! such as \function{sum()}, \function{min()}, \function{set()}, and
! \function{dict()}.  These functions consume their data all at once
! and would not benefit from having a full list instead of a generator
! as an input:
  
  \begin{verbatim}
--- 122,128 ----
  more readily than with list comprehensions.
  
! Generator expressions are best used in functions that consume their
! data all at once and would not benefit from having a full list instead
! of a generator as an input:
  
  \begin{verbatim}
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*** 150,158 ****
  \end{verbatim}     
  
- These examples show the intended use for generator expressions
- in situations where the values get consumed immediately after the
- generator is created.  In these situations, they operate like
- memory efficient versions of list comprehensions.
- 
  For more complex uses of generators, it is strongly recommended that
  the traditional full generator definitions be used instead.  In a
--- 148,151 ----
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*** 160,167 ****
  as soon as the expression is defined while the other expressions do
  not get evaluated until the generator is run.  This nuance is never
! an issue when the generator is used immediately.  If it is not used
! right away, then it is better to write a full generator definition
! which more clearly reveals when the expressions are evaluated and is
! more obvious about the visibility and lifetime of its looping variables.
  
  \begin{seealso}
--- 153,160 ----
  as soon as the expression is defined while the other expressions do
  not get evaluated until the generator is run.  This nuance is never
! an issue when the generator is used immediately; however, if it is not
! used right away, a full generator definition would be much more clear
! about when the sub-expressions are evaluated and would be more obvious
! about the visibility and lifetime of the variables.
  
  \begin{seealso}




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