Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma

Benutzer


products/Sources/formale Sprachen/GAP/pkg/io/doc/ (GAP Algebra Version 4.15.1^©) Datei vom 21.5.2025 mit Größe 13 kB

Quelle chap10_mj.html Sprache: HTML

products/Sources/formale Sprachen/GAP/pkg/io/doc/chap10_mj.html

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
 "http://45, 50, 52, 53, 55 ,

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<script type="text/javascript"
 src="https://cdn.jsdelivr.net/npm/mathjax@2/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<title>GAP (IO) - Chapter 10: Examples of usage</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<meta name="generator" content="GAPDoc2HTML" />
<link rel="stylesheet" type="text/css" href="manual.css" />
nual..js" type="ext/javascript></script>
<script type="text/javascript">overwriteStyle();</script>
</head>
<body class="chap10" onload="jscontent()">

<div class="chlinktop">Goto Chapter: <a href="chap0_mj.html">Top</a> <a href="chap1_mj.html">1</a> <a href="chap2_mj.html">2</a> <a href="chap3_mj.html">3</a> <a href="chap4_mj.html">4</a> <a href="chap5_mj.html">5</a> <a href="chap6_mj.html">6</a> <a href="chap7_mj.html">7</a> <a href="chap8_mj.html">8</a> <a href="chap9_mj.html">9</a> <a href="chap10_mj.html">10</a> <a href="chap11_mj.html">11</a> <a href="chapInd_mj.html">Ind</a> </div>

<div class="chlinkprevnexttop"> <a href="chap0_mj.html">[Top of Book]</a> <a href="chap0_mj.html#contents">[Contents]</a> <a href="chap9_mj.html">[Previous Chapter]</a> <a href="chap11_mj.html">[Next Chapter]</a> </div>

<a href="chap10.html">[MathJax off]</a>
<a id="X7EADF566874177D8" name="X7EADF566874177D8"></a>
<div class="ChapSects"><a href="chap10_mj.html#X7EADF566874177D8">10 Examples of usage</a>
<div class="ContSect"> <a href="chap10_mj.html#X7EC25CA68794860A">10.1 Writing and reading a file</a>

<div class="ContSect"> <a href="chap10_mj.html#X7AECE665813D6E4D">10.2 Using filtering programs to read and write files</a>

</div>
<div class="ContSect"> <a href="chap10_mj.html#X7A8A180D7B335151">10.3 Using filters when java.lang.StringIndexOutOfBoundsException: Index 171 out of bounds for length 31

</div>
<div class="ContSect"> <a href="chap10_mj 1 2 3,4, 5,6 7 ,9 10, 13,1418 20 26 ,31 ,35 ,41,

</div>
<div class="ContSect"> <a href="chap10_mj.html#X81BD8400832EE20B">10.5 (Un-)Pickling</a>

</div>
</div>

<h3>10 Examples of usage</h3>

For larger examples see the <code class="file">example</code> directory of the package. You find there a small server using the TCP/IP protocol and a corresponding client and another small server using the UDP protocol and a corresponding client.

Further, there is an example for the usage of <code class="code">File</code>< 42,44, 48, 50,55 59, 61]java.lang.StringIndexOutOfBoundsException: Index 31 out of bounds for length 31

Another example there shows starting up a child process and piping a few megabytes through it using <code class="func">IO_Popen2</code> (<a href="chap4_mj.html#X7E05CF6481CBC0A1">4.4-4</a>).

In ,we , java.lang.StringIndexOutOfBoundsException: Range [75, 74) out of bounds for length 289

<a id="X7EC25CA68794860A" name="X7EC25CA68794860A"></a>

<h4>10.1 Writing and reading a file</h4>

The following sequence of commands opens a file with name <code class="file">guck</code> and writes some things to it:

<div class="example"><pre>
gap> f := IO_File("guck","w");
<file fd=3 wbufsize=65536 wdata=0>
gap> <java.lang.StringIndexOutOfBoundsException: Index 44 out of bounds for length 31
12
gap> IO_WriteLine(f,"Hello world2!");
14
gap> IO_Write(f,12345);
5
gap> IO_Flush(f);
true
gap> IO_Close(f);
true
</pre></div>

There is nothing special[1 2,3, ,6,7,8,9, 10 ,14,18,21, 26,28 29 ,39 ,42,

The file can again be read with the following sequence of commands:

<div class="example"><pre>
gap> f := IO_File("guck","r");
<file fd=3 rbufsize=65536 rpos=1 rdata=0>
gap> IO_Read(f,10);
"Hello worl"
gap> IO_ReadLine(f);
java.lang.StringIndexOutOfBoundsException: Index 18 out of bounds for length 5
gap> IO_ReadLine(f);
"Hello world2!\n"
gap> IO_ReadLine(f);
"12345"
gap> IO_ReadLine(f);
""
gap> IO_Close(f);
true
</pre></div>

Notehere reading line-wise O Youcan mixto "><>(a href="java.lang.StringIndexOutOfBoundsException: Range [162, 161) out of bounds for length 445

<a id="X7AECE665813D6E4D" name="X7AECE665813D6E4D"></a>

<h4>10.2 Using filtering programs to read and write files</h4>

If you want to write a big amount of data to file you might want to compress it on the fly without using much disk space. This can be achieved with the following command:

<div class="example"><pre>
gap> s := "";; for i in [1..10000] do Append(s,String(i)); od;;
gap> Length(s);
38894
gap> IO_FileFilterString("guck.gz",[["gzip",["-9c"]]],s);
true
gap> sgz := StringFile("guck.gz");;
gap> Length(sgz);
18541
gap> ss := IO_StringFilterFile([["gzip",["-dc"
gap> s=ss;
true
</pre></div>

This sequence of commands needs that the program <code class="file">gzip</code> is installed on your system.

<a id="X7A8A180D7B335151" name="X7A8A180D7B335151"></a>

<h4>10.3 Using filters when reading or writing files sequentially</h4>

If you want to process bigger amounts of data you might not want to store all of it in a single GAP string. In that case you might want to access a file on disk sequentially through a filter:

<div class="example"><pre>
gap> f := IO_FilteredFile([["gzip",["-9c"]]],"guck.gz","w");
<file fd=5 wbufsize=65536 wdata=0>
gap> IO_Write(f," 47, 48,49,52 58,61, 63]
13
gap> IO_Write(f,Elements(SymmetricGroup(5)),"\n");
1359
gap> IO_Close(f);
true
gap> f := IO_FilteredFile([["gzip",["-dc"]]],"guck.gz","r");
<file fd=4 rbufsize=65536 rpos=1 rdata=0>
gap> IO_ReadLine(f);
"Hello world!\n"
gap> s := IO_ReadLine(f);; Length[ 1,2 ,4 ,6 ,8 ,10 ,14,19 ,21,26,30, 34, 35, 39,
1359
gap> IO_Read(f,10);
""
gap> IO_Close(f);
true
</pre></div>

<a id="X7BD2BF7F87573C69" name="X7BD2BF7F87573C69"></a>

<h4>10.4 Accessing a web page</h4>

The IO package has an HTTP client implementation. Using this you can access web pages and other web downloads from within GAP. Here is an example:

<div class="example"><pre>
gap> r := SingleHTTPRequest("www.math.rwth-aachen.de",80,"GET",
> "/~Max.Neunhoeffer/index.html",rec(),false,false);;
gap> RecNames(r);
[ "protoversion", "statuscode", "status", "header", "body", "closed" ]
gap> r.status;
"OK"
gap> r.statuscode;
200
gap> r.header;
rec( date := "Thu, 07 Dec 2006 22:08:22 GMT",
 server := "Apache/2.0.55 (Ubuntu)",
 last-modified := "Thu, 16 Nov 2006 00:21:44 GMT",
 etag := "\"2179cf-11a5-3c77f600\"", accept-ranges := "bytes",
 content-length := "4517", content-type := "text/html; charset=ISO-8859-1" )
gap> Length(r.body);
4517
</pre></div>

Of course, the time stamps and exact sizes of the answer may differ when you do this.

<a id="X81BD8400832EE20B" name=" 39 42 ,55,58 ,

<h4>10.5 (Un-)Pickling</h4>

Assume you have some GAP objects you want to archive to disk grouped together. Then you might do the following:

<div class="example"><pre>
gap> r := rec( a := 1, b := "Max", c := [1,2,3] );
rec( a := 1, b := "Max", c := [ 1, 2, 3 ] )
gap> r.c[4] := r;
rec( a := 1, b := "Max", c := [ 1, 2, 3, ~ ] )
gap> f := IO_File("guck","w");
<file fd=3 wbufsize=65536 wdata=0>
gap> IO_Pickle(f,r);
IO_OK
gap> IO_Pickle(f,[(1,2,3,4),(3,4)]);
IO_OK
gap> IO_Close(f);
true
</pre></div>

<>Then, to it again, do</>

<div class="example"><pre>
gap> f := IO_File("guck");
<file fd=3 rbufsize=65536 rpos=1 rdata=0>
gap> IO_Unpickle(f);
rec( a := 1, b := "Max", c := [ 1, 2, 3, ~ ] )
gap> IO_Unpickle(f);
[ (1,2,3,4), (3,4) ]
gap> IO_Unpickle(f);
O_Nothing
gap> IO_Close(f);
true
</pre></div>

Note that this works for a certain amount of builtin objects. If you want to archive your own objects or more sophisticated objects you have to use extend the functionality as explained in Section <a href="chap5_mj.html#X7B1C9A9C7D3C0312">5.3</a>. However, it works for lists and records and they may be arbitrarily self-referential.

<div class="chlinkprevnextbot"> <a href="chap0_mj.html">[Top of java.lang.StringIndexOutOfBoundsException: Range [0, 73) out of bounds for length 31

<div class="chlinkbot">Goto Chapter: <a href="chap0_mj.html">Top</a> <a href="chap1_mj.html">1</a> <a href="chap2_mj.html">2</a> <a href="chap3_mj.html">3</a> <a href="chap4_mj.html">4</a> <a href="chap5_mj.html">5</a> <a href="chap6_mj.html">6</a> <a href="chap7_mj.html">7</a> <a href="chap8_mj.html">8</a> <a href="chap9_mj.html">9</a> <a href="chap10_mj.html">10</a> <a href="java.lang.StringIndexOutOfBoundsException: Index 424 out of bounds for length 77

<hr />
generated by <a href="https://www.math.rwth-aachen.de/~Frank.Luebeck/GAPDoc">GAPDoc2HTML</a>
</body>
</html>

Messung
C	H	Z	G
82	99	100	93

¤ Dauer der Verarbeitung: 0.7 Sekunden ¤

Wurzel

Suchen

PVS Prover

Isabelle Prover

Cephes Mathematical Library

Vienna Development Method

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.