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  • Committer: Bazaar Package Importer
  • Author(s): Alexandre Fayolle
  • Date: 2006-06-28 10:45:03 UTC
  • mfrom: (1.2.1 upstream)
  • mto: This revision was merged to the branch mainline in revision 5.
  • Revision ID: james.westby@ubuntu.com-20060628104503-cc251q5o5j3e2k10
  * Fixed call to pyversions in debian/rules which failed on recent versions 
    of pyversions
  * Fixed clean rule in debian/rules which left the stamp files behind
  * Acknowledge NMU
  * Added Alexandre Fayolle to uploaders

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
 
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<HTML
 
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><HEAD
 
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><TITLE
 
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>FileNode module
 
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            reference</TITLE
 
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><META
 
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NAME="GENERATOR"
 
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CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
 
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REL="HOME"
 
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TITLE="PyTables User's Guide"
 
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HREF="index.html"><LINK
 
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REL="UP"
 
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TITLE="FileNode - simulating a filesystem with PyTables"
 
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HREF="c5708.html"><LINK
 
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REL="PREVIOUS"
 
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TITLE="Current limitations"
 
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HREF="x5885.html"><LINK
 
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REL="NEXT"
 
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TITLE="NetCDF - a PyTables
 
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          NetCDF3 emulation API"
 
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HREF="c6061.html"></HEAD
 
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><BODY
 
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CLASS="sect1"
 
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BGCOLOR="#FFFFFF"
 
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TEXT="#000000"
 
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LINK="#0000FF"
 
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VLINK="#840084"
 
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ALINK="#0000FF"
 
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><DIV
 
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CLASS="NAVHEADER"
 
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><TABLE
 
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SUMMARY="Header navigation table"
 
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WIDTH="100%"
 
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BORDER="0"
 
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CELLPADDING="0"
 
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CELLSPACING="0"
 
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><TR
 
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><TH
 
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COLSPAN="3"
 
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ALIGN="center"
 
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><SPAN
 
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CLASS="markup"
 
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>PyTables</SPAN
 
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> User's Guide: Hierarchical datasets in Python - Release 1.3.2</TH
 
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></TR
 
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><TR
 
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><TD
 
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WIDTH="10%"
 
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ALIGN="left"
 
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VALIGN="bottom"
 
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><A
 
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HREF="x5885.html"
 
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ACCESSKEY="P"
 
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>Prev</A
 
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></TD
 
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><TD
 
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WIDTH="80%"
 
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ALIGN="center"
 
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VALIGN="bottom"
 
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>Chapter 6. FileNode - simulating a filesystem with <SPAN
 
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CLASS="markup"
 
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>PyTables</SPAN
 
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></TD
 
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><TD
 
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WIDTH="10%"
 
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ALIGN="right"
 
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VALIGN="bottom"
 
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><A
 
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HREF="c6061.html"
 
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>Next</A
 
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></TD
 
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></TR
 
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></TABLE
 
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><HR
 
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ALIGN="LEFT"
 
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WIDTH="100%"></DIV
 
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><DIV
 
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CLASS="sect1"
 
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><H1
 
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CLASS="sect1"
 
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><A
 
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NAME="section6.6"
 
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>6.6. <SPAN
 
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CLASS="markup"
 
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>FileNode</SPAN
 
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> module
 
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            reference</A
 
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></H1
 
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><DIV
 
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CLASS="sect2"
 
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><H2
 
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CLASS="sect2"
 
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><A
 
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NAME="subsection6.6.1"
 
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>6.6.1. Global constants</A
 
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></H2
 
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><DIV
 
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CLASS="glosslist"
 
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><DL
 
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><DT
 
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><B
 
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>NodeType</B
 
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></DT
 
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><DD
 
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><P
 
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>Value for <SAMP
 
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CLASS="computeroutput"
 
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>NODE_TYPE</SAMP
 
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>
 
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                node system attribute.</P
 
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></DD
 
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><DT
 
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><B
 
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>NodeTypeVersions</B
 
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></DT
 
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><DD
 
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><P
 
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>Supported values for
 
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                <SAMP
 
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CLASS="computeroutput"
 
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>NODE_TYPE_VERSION</SAMP
 
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> node system attribute.</P
 
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></DD
 
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></DL
 
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></DIV
 
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></DIV
 
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><DIV
 
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CLASS="sect2"
 
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><H2
 
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CLASS="sect2"
 
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><A
 
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NAME="subsection6.6.2"
 
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>6.6.2. Global functions</A
 
136
></H2
 
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><DIV
 
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CLASS="sect3"
 
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><H3
 
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CLASS="sect3"
 
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><A
 
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NAME="subsubsection6.6.2.1"
 
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>6.6.2.1. newNode(h5file, where, name, title="",
 
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                filters=None, expectedsize=1000)</A
 
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></H3
 
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><P
 
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>Creates a new file node object in the specified
 
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                <SAMP
 
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CLASS="computeroutput"
 
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>PyTables</SAMP
 
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> file object.  Additional named
 
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                arguments <SAMP
 
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CLASS="computeroutput"
 
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>where</SAMP
 
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> and <SAMP
 
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CLASS="computeroutput"
 
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>name</SAMP
 
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> must
 
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                be passed to specify where the file node is to be
 
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                created.  Other named arguments such as
 
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                <SAMP
 
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CLASS="computeroutput"
 
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>title</SAMP
 
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> and <SAMP
 
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CLASS="computeroutput"
 
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>filters</SAMP
 
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> may also be
 
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                passed. The special named argument
 
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                <SAMP
 
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CLASS="computeroutput"
 
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>expectedsize</SAMP
 
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>, indicating an estimate of the
 
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                file size in bytes, may also be passed. It returns the
 
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                file node object.
 
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              </P
 
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></DIV
 
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><DIV
 
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CLASS="sect3"
 
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><H3
 
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CLASS="sect3"
 
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><A
 
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NAME="subsubsection6.6.2.2"
 
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>6.6.2.2. openNode(node, mode = 'r')</A
 
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></H3
 
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><P
 
186
>Opens an existing file node. Returns a file node object
 
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                from the existing specified PyTables node.  If mode is
 
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                not specified or it is <SAMP
 
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CLASS="computeroutput"
 
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>'r'</SAMP
 
191
>, the file can
 
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                only be read, and the pointer is positioned at the
 
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                beginning of the file.  If mode is <SAMP
 
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CLASS="computeroutput"
 
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>'a+'</SAMP
 
196
>,
 
197
                the file can be read and appended, and the pointer is
 
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                positioned at the end of the file.
 
199
              </P
 
200
></DIV
 
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></DIV
 
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><DIV
 
203
CLASS="sect2"
 
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><H2
 
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CLASS="sect2"
 
206
><A
 
207
NAME="subsection6.6.3"
 
208
>6.6.3. The <SPAN
 
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CLASS="markup"
 
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>FileNode</SPAN
 
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>
 
212
              abstract class</A
 
213
></H2
 
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><P
 
215
>This is the ancestor of <SAMP
 
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CLASS="computeroutput"
 
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>ROFileNode</SAMP
 
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> and
 
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              <SAMP
 
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CLASS="computeroutput"
 
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>RAFileNode</SAMP
 
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> (see below). Instances of these
 
223
              classes are returned when <SAMP
 
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CLASS="computeroutput"
 
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>newNode()</SAMP
 
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> or
 
227
              <SAMP
 
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CLASS="computeroutput"
 
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>openNode()</SAMP
 
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> are called. It represents a new
 
231
              file node associated with a <SAMP
 
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CLASS="computeroutput"
 
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>PyTables</SAMP
 
234
> node,
 
235
              providing a standard Python file interface to it.
 
236
            </P
 
237
><P
 
238
>This abstract class provides only an implementation of
 
239
              the reading methods needed to implement a file-like object
 
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              over a <SAMP
 
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CLASS="computeroutput"
 
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>PyTables</SAMP
 
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> node.  The attribute set of
 
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              the node becomes available via the <SAMP
 
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CLASS="computeroutput"
 
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>attrs</SAMP
 
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>
 
248
              property.  You can add attributes there, but try to avoid
 
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              attribute names in all caps or starting with
 
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              <SAMP
 
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CLASS="computeroutput"
 
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>'_'</SAMP
 
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>, since they may clash with internal
 
254
              attributes.
 
255
            </P
 
256
><P
 
257
>The node used as storage is also made available via the
 
258
              read-only attribute <SAMP
 
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CLASS="computeroutput"
 
260
>node</SAMP
 
261
>.  Please do not
 
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              tamper with this object unless unavoidably, since you may
 
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              break the operation of the file node object.
 
264
            </P
 
265
><P
 
266
>The <SAMP
 
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CLASS="computeroutput"
 
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>lineSeparator</SAMP
 
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> property contains the
 
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              string used as a line separator, and defaults to
 
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              <SAMP
 
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CLASS="computeroutput"
 
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>os.linesep</SAMP
 
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>.  It can be set to any
 
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              reasonably-sized string you want.
 
276
            </P
 
277
><P
 
278
>The constructor sets the <SAMP
 
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CLASS="computeroutput"
 
280
>closed</SAMP
 
281
>,
 
282
              <SAMP
 
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CLASS="computeroutput"
 
284
>softspace</SAMP
 
285
> and <SAMP
 
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CLASS="computeroutput"
 
287
>_lineSeparator</SAMP
 
288
>
 
289
              attributes to their initial values, as well as the
 
290
              <SAMP
 
291
CLASS="computeroutput"
 
292
>node</SAMP
 
293
> attribute to <SAMP
 
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CLASS="computeroutput"
 
295
>None</SAMP
 
296
>.
 
297
              Sub-classes should set the <SAMP
 
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CLASS="computeroutput"
 
299
>node</SAMP
 
300
>,
 
301
              <SAMP
 
302
CLASS="computeroutput"
 
303
>mode</SAMP
 
304
> and <SAMP
 
305
CLASS="computeroutput"
 
306
>offset</SAMP
 
307
> attributes.
 
308
            </P
 
309
><P
 
310
>Version 1 implements the file storage as a
 
311
              <SAMP
 
312
CLASS="computeroutput"
 
313
>UInt8</SAMP
 
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> uni-dimensional <SAMP
 
315
CLASS="computeroutput"
 
316
>EArray</SAMP
 
317
>.
 
318
            </P
 
319
><DIV
 
320
CLASS="sect3"
 
321
><H3
 
322
CLASS="sect3"
 
323
><A
 
324
NAME="subsubsection6.6.3.1"
 
325
>6.6.3.1. <SPAN
 
326
CLASS="markup"
 
327
>FileNode</SPAN
 
328
>
 
329
                methods</A
 
330
></H3
 
331
><DIV
 
332
CLASS="glosslist"
 
333
><DL
 
334
><DT
 
335
><B
 
336
>getLineSeparator()</B
 
337
></DT
 
338
><DD
 
339
><P
 
340
>Returns the line
 
341
                  separator string.</P
 
342
></DD
 
343
><DT
 
344
><B
 
345
>setLineSeparator()</B
 
346
></DT
 
347
><DD
 
348
><P
 
349
>Sets the line
 
350
                  separator string.</P
 
351
></DD
 
352
><DT
 
353
><B
 
354
>getAttrs()</B
 
355
></DT
 
356
><DD
 
357
><P
 
358
>Returns the attribute set
 
359
                  of the file node.</P
 
360
></DD
 
361
><DT
 
362
><B
 
363
>close()</B
 
364
></DT
 
365
><DD
 
366
><P
 
367
>Flushes the file and closes
 
368
                  it.  The <SAMP
 
369
CLASS="computeroutput"
 
370
>node</SAMP
 
371
> attribute becomes
 
372
                  <SAMP
 
373
CLASS="computeroutput"
 
374
>None</SAMP
 
375
> and the <SAMP
 
376
CLASS="computeroutput"
 
377
>attrs</SAMP
 
378
> property
 
379
                  becomes no longer available.</P
 
380
></DD
 
381
><DT
 
382
><B
 
383
>next()</B
 
384
></DT
 
385
><DD
 
386
><P
 
387
>Returns the next line of text.
 
388
                  Raises <SAMP
 
389
CLASS="computeroutput"
 
390
>StopIteration</SAMP
 
391
> when lines are
 
392
                  exhausted.  See <SAMP
 
393
CLASS="computeroutput"
 
394
>file.next.__doc__</SAMP
 
395
> for
 
396
                  more information.</P
 
397
></DD
 
398
><DT
 
399
><B
 
400
>read(size=None)</B
 
401
></DT
 
402
><DD
 
403
><P
 
404
>Reads at most
 
405
                  <SAMP
 
406
CLASS="computeroutput"
 
407
>size</SAMP
 
408
> bytes.  See
 
409
                  <SAMP
 
410
CLASS="computeroutput"
 
411
>file.read.__doc__</SAMP
 
412
> for more
 
413
                  information</P
 
414
></DD
 
415
><DT
 
416
><B
 
417
>readline(size=-1)</B
 
418
></DT
 
419
><DD
 
420
><P
 
421
>Reads the next text
 
422
                  line.  See <SAMP
 
423
CLASS="computeroutput"
 
424
>file.readline.__doc__</SAMP
 
425
> for more
 
426
                  information</P
 
427
></DD
 
428
><DT
 
429
><B
 
430
>readlines(sizehint=-1)</B
 
431
></DT
 
432
><DD
 
433
><P
 
434
>Reads the text
 
435
                  lines.  See <SAMP
 
436
CLASS="computeroutput"
 
437
>file.readlines.__doc__</SAMP
 
438
> for
 
439
                  more information.</P
 
440
></DD
 
441
><DT
 
442
><B
 
443
>seek(offset, whence=0)</B
 
444
></DT
 
445
><DD
 
446
><P
 
447
>Moves to a new
 
448
                  file position.  See <SAMP
 
449
CLASS="computeroutput"
 
450
>file.seek.__doc__</SAMP
 
451
> for
 
452
                  more information.</P
 
453
></DD
 
454
><DT
 
455
><B
 
456
>tell()</B
 
457
></DT
 
458
><DD
 
459
><P
 
460
> Gets the current file
 
461
                  position.  See <SAMP
 
462
CLASS="computeroutput"
 
463
>file.tell.__doc__</SAMP
 
464
> for more
 
465
                  information.</P
 
466
></DD
 
467
><DT
 
468
><B
 
469
>xreadlines()</B
 
470
></DT
 
471
><DD
 
472
><P
 
473
>For backward
 
474
                  compatibility.  See
 
475
                  <SAMP
 
476
CLASS="computeroutput"
 
477
>file.xreadlines.__doc__</SAMP
 
478
> for more
 
479
                  information.</P
 
480
></DD
 
481
></DL
 
482
></DIV
 
483
></DIV
 
484
></DIV
 
485
><DIV
 
486
CLASS="sect2"
 
487
><H2
 
488
CLASS="sect2"
 
489
><A
 
490
NAME="subsection6.6.4"
 
491
>6.6.4. The <SPAN
 
492
CLASS="markup"
 
493
>ROFileNode</SPAN
 
494
>
 
495
              class</A
 
496
></H2
 
497
><P
 
498
>Instances of this class are returned when
 
499
              <SAMP
 
500
CLASS="computeroutput"
 
501
>openNode()</SAMP
 
502
> is called in read-only mode
 
503
              (<SAMP
 
504
CLASS="computeroutput"
 
505
>'r'</SAMP
 
506
>). This is a descendant of
 
507
              <SAMP
 
508
CLASS="computeroutput"
 
509
>FileNode</SAMP
 
510
> class, so it inherits all its
 
511
              methods. Moreover, it does not define any other useful
 
512
              method, just some protections against users intents to
 
513
              write on file.
 
514
            </P
 
515
></DIV
 
516
><DIV
 
517
CLASS="sect2"
 
518
><H2
 
519
CLASS="sect2"
 
520
><A
 
521
NAME="subsection6.6.5"
 
522
>6.6.5. The <SPAN
 
523
CLASS="markup"
 
524
>RAFileNode</SPAN
 
525
>
 
526
              class</A
 
527
></H2
 
528
><P
 
529
>Instances of this class are returned when either
 
530
              <SAMP
 
531
CLASS="computeroutput"
 
532
>newNode()</SAMP
 
533
> is called or when
 
534
              <SAMP
 
535
CLASS="computeroutput"
 
536
>openNode()</SAMP
 
537
> is called in append mode
 
538
              (<SAMP
 
539
CLASS="computeroutput"
 
540
>'a+'</SAMP
 
541
>). This is a descendant of
 
542
              <SAMP
 
543
CLASS="computeroutput"
 
544
>FileNode</SAMP
 
545
> class, so it inherits all its
 
546
              methods. It provides additional methods that allow to
 
547
              write on file nodes.
 
548
            </P
 
549
><DIV
 
550
CLASS="glosslist"
 
551
><DL
 
552
><DT
 
553
><B
 
554
>flush()</B
 
555
></DT
 
556
><DD
 
557
><P
 
558
>Flushes the file node.  See
 
559
                <SAMP
 
560
CLASS="computeroutput"
 
561
>file.flush.__doc__</SAMP
 
562
> for more
 
563
                information.</P
 
564
></DD
 
565
><DT
 
566
><B
 
567
>truncate(size=None)</B
 
568
></DT
 
569
><DD
 
570
><P
 
571
>Truncates the file
 
572
                node to at most <SAMP
 
573
CLASS="computeroutput"
 
574
>size</SAMP
 
575
> bytes. Currently, this
 
576
                method only makes sense to grow the file node, since
 
577
                data can not be rewritten nor deleted.  See
 
578
                <SAMP
 
579
CLASS="computeroutput"
 
580
>file.truncate.__doc__</SAMP
 
581
> for more
 
582
                information.</P
 
583
></DD
 
584
><DT
 
585
><B
 
586
>write(string)</B
 
587
></DT
 
588
><DD
 
589
><P
 
590
>Writes the string to the
 
591
                file.  Writing an empty string does nothing, but
 
592
                requires the file to be open.  See
 
593
                <SAMP
 
594
CLASS="computeroutput"
 
595
>file.write.__doc__</SAMP
 
596
> for more
 
597
                information.</P
 
598
></DD
 
599
><DT
 
600
><B
 
601
>writelines(sequence)</B
 
602
></DT
 
603
><DD
 
604
><P
 
605
>Writes the
 
606
                sequence of strings to the file.  See
 
607
                <SAMP
 
608
CLASS="computeroutput"
 
609
>file.writelines.__doc__</SAMP
 
610
> for more
 
611
                information.</P
 
612
></DD
 
613
></DL
 
614
></DIV
 
615
></DIV
 
616
></DIV
 
617
><DIV
 
618
CLASS="NAVFOOTER"
 
619
><HR
 
620
ALIGN="LEFT"
 
621
WIDTH="100%"><TABLE
 
622
SUMMARY="Footer navigation table"
 
623
WIDTH="100%"
 
624
BORDER="0"
 
625
CELLPADDING="0"
 
626
CELLSPACING="0"
 
627
><TR
 
628
><TD
 
629
WIDTH="33%"
 
630
ALIGN="left"
 
631
VALIGN="top"
 
632
><A
 
633
HREF="x5885.html"
 
634
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>Prev</A
 
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WIDTH="34%"
 
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ALIGN="center"
 
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><A
 
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HREF="index.html"
 
643
ACCESSKEY="H"
 
644
>Home</A
 
645
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WIDTH="33%"
 
648
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>Current limitations</TD
 
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HREF="c5708.html"
 
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>Up</A
 
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672
WIDTH="33%"
 
673
ALIGN="right"
 
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VALIGN="top"
 
675
>NetCDF - a <SPAN
 
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CLASS="markup"
 
677
>PyTables</SPAN
 
678
>
 
679
          NetCDF3 emulation API</TD
 
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>
 
 
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