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| 54 | <H1><A NAME="SECTION00142000000000000000000"> |
| 55 | 12.20 <tt class="module">csv</tt> -- CSV File Reading and Writing</A> |
| 56 | </H1> |
| 57 | |
| 58 | <P> |
| 59 | <A NAME="module-csv"></A> |
| 60 | |
| 61 | <P> |
| 62 | |
| 63 | <span class="versionnote">New in version 2.3.</span> |
| 64 | |
| 65 | <a id='l2h-4212' xml:id='l2h-4212'></a> |
| 66 | <a id='l2h-4211' xml:id='l2h-4211'></a> |
| 67 | <P> |
| 68 | The so-called CSV (Comma Separated Values) format is the most common import |
| 69 | and export format for spreadsheets and databases. There is no ``CSV |
| 70 | standard'', so the format is operationally defined by the many applications |
| 71 | which read and write it. The lack of a standard means that subtle |
| 72 | differences often exist in the data produced and consumed by different |
| 73 | applications. These differences can make it annoying to process CSV files |
| 74 | from multiple sources. Still, while the delimiters and quoting characters |
| 75 | vary, the overall format is similar enough that it is possible to write a |
| 76 | single module which can efficiently manipulate such data, hiding the details |
| 77 | of reading and writing the data from the programmer. |
| 78 | |
| 79 | <P> |
| 80 | The <tt class="module">csv</tt> module implements classes to read and write tabular data in |
| 81 | CSV format. It allows programmers to say, ``write this data in the format |
| 82 | preferred by Excel,'' or ``read data from this file which was generated by |
| 83 | Excel,'' without knowing the precise details of the CSV format used by |
| 84 | Excel. Programmers can also describe the CSV formats understood by other |
| 85 | applications or define their own special-purpose CSV formats. |
| 86 | |
| 87 | <P> |
| 88 | The <tt class="module">csv</tt> module's <tt class="class">reader</tt> and <tt class="class">writer</tt> objects read and |
| 89 | write sequences. Programmers can also read and write data in dictionary |
| 90 | form using the <tt class="class">DictReader</tt> and <tt class="class">DictWriter</tt> classes. |
| 91 | |
| 92 | <P> |
| 93 | <div class="note"><b class="label">Note:</b> |
| 94 | This version of the <tt class="module">csv</tt> module doesn't support Unicode |
| 95 | input. Also, there are currently some issues regarding ASCII NUL |
| 96 | characters. Accordingly, all input should generally be printable |
| 97 | ASCII to be safe. These restrictions will be removed in the future. |
| 98 | </div> |
| 99 | |
| 100 | <P> |
| 101 | <div class="seealso"> |
| 102 | <p class="heading">See Also:</p> |
| 103 | |
| 104 | <dl compact="compact" class="seerfc"> |
| 105 | <dt><a href="http://www.python.org/peps/pep-0305.html" |
| 106 | title="CSV File API" |
| 107 | >PEP 305, <em>CSV File API</em></a> |
| 108 | <dd>The Python Enhancement Proposal which proposed this addition |
| 109 | to Python. |
| 110 | </dl> |
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| 112 | |
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| 117 | <!--Table of Child-Links--> |
| 118 | <A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></a> |
| 119 | |
| 120 | <UL CLASS="ChildLinks"> |
| 121 | <LI><A href="csv-contents.html">12.20.1 Module Contents</a> |
| 122 | <LI><A href="csv-fmt-params.html">12.20.2 Dialects and Formatting Parameters</a> |
| 123 | <LI><A href="node634.html">12.20.3 Reader Objects</a> |
| 124 | <LI><A href="node635.html">12.20.4 Writer Objects</a> |
| 125 | <LI><A href="node636.html">12.20.5 Examples</a> |
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| 164 | <span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span> |
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