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| -rw-r--r-- | Doc/whatsnew/whatsnew23.tex | 50 |
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diff --git a/Doc/whatsnew/whatsnew23.tex b/Doc/whatsnew/whatsnew23.tex index 0e3bf40..4a2b18f 100644 --- a/Doc/whatsnew/whatsnew23.tex +++ b/Doc/whatsnew/whatsnew23.tex @@ -834,6 +834,56 @@ Implemented by Just van~Rossum. %====================================================================== +\section{PEP 305: Comma-separated Files \label{section-pep305}} + +Comma-separated files are a format frequently used for exporting data +from databases and spreadsheets. Python 2.3 adds a parser for +comma-separated files. +The format is deceptively simple at first glance: + +\begin{verbatim} +Costs,150,200,3.95 +\end{verbatim} + +Read a line and call \code{line.split(',')}: what could be simpler? +But toss in string data that can contain commas, and things get more +complicated: + +\begin{verbatim} +"Costs",150,200,3.95,"Includes taxes, shipping, and sundry items" +\end{verbatim} + +A big ugly regular expression can parse this, but using the new +\module{csv} package is much simpler: + +\begin{verbatim} +from csv import csv + +input = open('datafile', 'rb') +reader = csv.reader(input) +for line in reader: + print line +\end{verbatim} + +The \function{reader} function takes a number of different options. +The field separator isn't limited to the comma and can be changed to +any character, and so can the quoting and line-ending characters. + +Different dialects of comma-separated files can be defined and +registered; currently there are two, both for Microsoft Excel. +A separate \class{csv.writer} class will generate comma-separated files +from a succession of tuples or lists, quoting strings that contain the +delimiter. + +\begin{seealso} + +\seepep{305}{CSV File API}{Written and implemented +by Kevin Altis, Dave Cole, Andrew McNamara, Skip Montanaro, Cliff Wells. +} + +\end{seealso} + +%====================================================================== \section{Extended Slices\label{section-slices}} Ever since Python 1.4, the slicing syntax has supported an optional |