1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ -->
<head>
<title>Maxima 5.45.1 Manual: Introduction to String Processing</title>
<meta name="description" content="Maxima 5.45.1 Manual: Introduction to String Processing">
<meta name="keywords" content="Maxima 5.45.1 Manual: Introduction to String Processing">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link href="maxima_0.html#Top" rel="start" title="Top">
<link href="maxima_368.html#Function-and-Variable-Index" rel="index" title="Function and Variable Index">
<link href="maxima_toc.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="maxima_330.html#stringproc_002dpkg" rel="up" title="stringproc-pkg">
<link href="maxima_332.html#Input-and-Output" rel="next" title="Input and Output">
<link href="maxima_330.html#stringproc_002dpkg" rel="previous" title="stringproc-pkg">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.indentedblock {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
div.smalllisp {margin-left: 3.2em}
kbd {font-style:oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nocodebreak {white-space:nowrap}
span.nolinebreak {white-space:nowrap}
span.roman {font-family:serif; font-weight:normal}
span.sansserif {font-family:sans-serif; font-weight:normal}
ul.no-bullet {list-style: none}
body {color: black; background: white; margin-left: 8%; margin-right: 13%;
font-family: "FreeSans", sans-serif}
h1 {font-size: 150%; font-family: "FreeSans", sans-serif}
h2 {font-size: 125%; font-family: "FreeSans", sans-serif}
h3 {font-size: 100%; font-family: "FreeSans", sans-serif}
a[href] {color: rgb(0,0,255); text-decoration: none;}
a[href]:hover {background: rgb(220,220,220);}
div.textbox {border: solid; border-width: thin; padding-top: 1em;
padding-bottom: 1em; padding-left: 2em; padding-right: 2em}
div.titlebox {border: none; padding-top: 1em; padding-bottom: 1em;
padding-left: 2em; padding-right: 2em; background: rgb(200,255,255);
font-family: sans-serif}
div.synopsisbox {
border: none; padding-top: 1em; padding-bottom: 1em; padding-left: 2em;
padding-right: 2em; background: rgb(255,220,255);}
pre.example {border: 1px solid rgb(180,180,180); padding-top: 1em;
padding-bottom: 1em; padding-left: 1em; padding-right: 1em;
background-color: rgb(238,238,255)}
div.spacerbox {border: none; padding-top: 2em; padding-bottom: 2em}
div.image {margin: 0; padding: 1em; text-align: center}
div.categorybox {border: 1px solid gray; padding-top: 0px; padding-bottom: 0px;
padding-left: 1em; padding-right: 1em; background: rgb(247,242,220)}
img {max-width:80%; max-height: 80%; display: block; margin-left: auto; margin-right: auto}
-->
</style>
<link rel="icon" href="figures/favicon.ico">
</head>
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
<a name="Introduction-to-String-Processing"></a>
<div class="header">
<p>
Next: <a href="maxima_332.html#Input-and-Output" accesskey="n" rel="next">Input and Output</a>, Previous: <a href="maxima_330.html#stringproc_002dpkg" accesskey="p" rel="previous">stringproc-pkg</a>, Up: <a href="maxima_330.html#stringproc_002dpkg" accesskey="u" rel="up">stringproc-pkg</a> [<a href="maxima_toc.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="maxima_368.html#Function-and-Variable-Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Introduction-to-String-Processing-1"></a>
<h3 class="section">88.1 Introduction to String Processing</h3>
<p>The package <code>stringproc</code> contains functions for processing strings
and characters including formatting, encoding and data streams.
This package is completed by some tools for cryptography, e.g. base64 and hash
functions.
</p>
<p>It can be directly loaded via <code>load(stringproc)</code> or automatically by
using one of its functions.
</p>
<p>For questions and bug reports please contact the author. The following
command prints his e-mail-address.
</p>
<p><code>printf(true, "~{~a~}@gmail.com", split(sdowncase("Volker van Nek")))$</code>
</p>
<p>A string is constructed by typing e.g. <code>"Text"</code>.
When the option variable <code><a href="maxima_16.html#stringdisp">stringdisp</a></code> is set to <code>false</code>, which is
the default, the double quotes won’t be printed.
<a href="maxima_334.html#stringp">stringp</a> is a test, if an object is a string.
</p>
<div class="example">
<pre class="example">(%i1) str: "Text";
(%o1) Text
(%i2) stringp(str);
(%o2) true
</pre></div>
<p>Characters are represented by a string of length 1.
<a href="maxima_333.html#charp">charp</a> is the corresponding test.
</p>
<div class="example">
<pre class="example">(%i1) char: "e";
(%o1) e
(%i2) charp(char);
(%o2) true
</pre></div>
<p>In Maxima position indices in strings are like in list 1-indexed
which results to the following consistency.
</p>
<div class="example">
<pre class="example">(%i1) is(charat("Lisp",1) = charlist("Lisp")[1]);
(%o1) true
</pre></div>
<p>A string may contain Maxima expressions.
These can be parsed with <a href="maxima_334.html#parse_005fstring">parse_string</a>.
</p>
<div class="example">
<pre class="example">(%i1) map(parse_string, ["42" ,"sqrt(2)", "%pi"]);
(%o1) [42, sqrt(2), %pi]
(%i2) map('float, %);
(%o2) [42.0, 1.414213562373095, 3.141592653589793]
</pre></div>
<p>Strings can be processed as characters or in binary form as octets.
Functions for conversions are <a href="maxima_335.html#string_005fto_005foctets">string_to_octets</a> and <a href="maxima_335.html#octets_005fto_005fstring">octets_to_string</a>.
Usable encodings depend on the platform, the application and the
underlying Lisp.
(The following shows Maxima in GNU/Linux, compiled with SBCL.)
</p>
<div class="example">
<pre class="example">(%i1) obase: 16.$
(%i2) string_to_octets("$£€", "cp1252");
(%o2) [24, 0A3, 80]
(%i3) string_to_octets("$£€", "utf-8");
(%o3) [24, 0C2, 0A3, 0E2, 82, 0AC]
</pre></div>
<p>Strings may be written to character streams or as octets to binary streams.
The following example demonstrates file in and output of characters.
</p>
<p><a href="maxima_332.html#openw">openw</a> returns an output stream to a file,
<a href="maxima_332.html#printf">printf</a> writes formatted to that file and by e.g.
<a href="maxima_332.html#close">close</a> all characters contained in the stream are written to the file.
</p>
<div class="example">
<pre class="example">(%i1) s: openw("file.txt");
(%o1) #<output stream file.txt>
(%i2) printf(s, "~%~d ~f ~a ~a ~f ~e ~a~%",
42, 1.234, sqrt(2), %pi, 1.0e-2, 1.0e-2, 1.0b-2)$
(%i3) close(s)$
</pre></div>
<p><a href="maxima_332.html#openr">openr</a> then returns an input stream from the previously used file and
<a href="maxima_332.html#readline">readline</a> returns the line read as a string.
The string may be tokenized by e.g. <a href="maxima_334.html#split">split</a> or <a href="maxima_334.html#tokens">tokens</a> and
finally parsed by <a href="maxima_334.html#parse_005fstring">parse_string</a>.
</p>
<div class="example">
<pre class="example">(%i4) s: openr("file.txt");
(%o4) #<input stream file.txt>
(%i5) readline(s);
(%o5) 42 1.234 sqrt(2) %pi 0.01 1.0E-2 1.0b-2
(%i6) map(parse_string, split(%));
(%o6) [42, 1.234, sqrt(2), %pi, 0.01, 0.01, 1.0b-2]
(%i7) close(s)$
</pre></div>
<div class=categorybox>·<p>Categories: <a href="maxima_369.html#Category_003a-Strings">Strings</a>
·<a href="maxima_369.html#Category_003a-Share-packages">Share packages</a>
·<a href="maxima_369.html#Category_003a-Package-stringproc">Package stringproc</a>
</div></p>
<a name="Item_003a-stringproc_002fnode_002fInput-and-Output"></a><hr>
<div class="header">
<p>
Next: <a href="maxima_332.html#Input-and-Output" accesskey="n" rel="next">Input and Output</a>, Previous: <a href="maxima_330.html#stringproc_002dpkg" accesskey="p" rel="previous">stringproc-pkg</a>, Up: <a href="maxima_330.html#stringproc_002dpkg" accesskey="u" rel="up">stringproc-pkg</a> [<a href="maxima_toc.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="maxima_368.html#Function-and-Variable-Index" title="Index" rel="index">Index</a>]</p>
</div>
</body>
</html>
|
