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
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
|
<html lang="en">
<head>
<title>String Conversions - Untitled</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="Untitled">
<meta name="generator" content="makeinfo 4.11">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Strings.html#Strings" title="Strings">
<link rel="prev" href="Manipulating-Strings.html#Manipulating-Strings" title="Manipulating Strings">
<link rel="next" href="Character-Class-Functions.html#Character-Class-Functions" title="Character Class Functions">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<p>
<a name="String-Conversions"></a>
Next: <a rel="next" accesskey="n" href="Character-Class-Functions.html#Character-Class-Functions">Character Class Functions</a>,
Previous: <a rel="previous" accesskey="p" href="Manipulating-Strings.html#Manipulating-Strings">Manipulating Strings</a>,
Up: <a rel="up" accesskey="u" href="Strings.html#Strings">Strings</a>
<hr>
</div>
<h3 class="section">5.6 String Conversions</h3>
<p>Octave supports various kinds of conversions between strings and
numbers. As an example, it is possible to convert a string containing
a hexadecimal number to a floating point number.
<pre class="example"> hex2dec ("FF")
ans = 255
</pre>
<!-- ./strings/bin2dec.m -->
<p><a name="doc_002dbin2dec"></a>
<div class="defun">
— Function File: <b>bin2dec</b> (<var>s</var>)<var><a name="index-bin2dec-335"></a></var><br>
<blockquote><p>Return the decimal number corresponding to the binary number stored
in the string <var>s</var>. For example,
<pre class="example"> bin2dec ("1110")
14
</pre>
<p>If <var>s</var> is a string matrix, returns a column vector of converted
numbers, one per row of <var>s</var>. Invalid rows evaluate to NaN.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>, <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>.
</p></blockquote></div>
<!-- ./strings/dec2bin.m -->
<p><a name="doc_002ddec2bin"></a>
<div class="defun">
— Function File: <b>dec2bin</b> (<var>n, len</var>)<var><a name="index-dec2bin-336"></a></var><br>
<blockquote><p>Return a binary number corresponding to the non-negative decimal number
<var>n</var>, as a string of ones and zeros. For example,
<pre class="example"> dec2bin (14)
"1110"
</pre>
<p>If <var>n</var> is a vector, returns a string matrix, one row per value,
padded with leading zeros to the width of the largest value.
<p>The optional second argument, <var>len</var>, specifies the minimum
number of digits in the result.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- ./strings/dec2hex.m -->
<p><a name="doc_002ddec2hex"></a>
<div class="defun">
— Function File: <b>dec2hex</b> (<var>n, len</var>)<var><a name="index-dec2hex-337"></a></var><br>
<blockquote><p>Return the hexadecimal string corresponding to the non-negative
integer <var>n</var>. For example,
<pre class="example"> dec2hex (2748)
"ABC"
</pre>
<p>If <var>n</var> is a vector, returns a string matrix, one row per value,
padded with leading zeros to the width of the largest value.
<p>The optional second argument, <var>len</var>, specifies the minimum
number of digits in the result.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>.
</p></blockquote></div>
<!-- ./strings/hex2dec.m -->
<p><a name="doc_002dhex2dec"></a>
<div class="defun">
— Function File: <b>hex2dec</b> (<var>s</var>)<var><a name="index-hex2dec-338"></a></var><br>
<blockquote><p>Return the integer corresponding to the hexadecimal number stored
in the string <var>s</var>. For example,
<pre class="example"> hex2dec ("12B")
299
hex2dec ("12b")
299
</pre>
<p>If <var>s</var> is a string matrix, returns a column vector of converted
numbers, one per row of <var>s</var>. Invalid rows evaluate to NaN.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>, <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>.
</p></blockquote></div>
<!-- ./strings/dec2base.m -->
<p><a name="doc_002ddec2base"></a>
<div class="defun">
— Function File: <b>dec2base</b> (<var>n, b, len</var>)<var><a name="index-dec2base-339"></a></var><br>
<blockquote><p>Return a string of symbols in base <var>b</var> corresponding to
the non-negative integer <var>n</var>.
<pre class="example"> dec2base (123, 3)
"11120"
</pre>
<p>If <var>n</var> is a vector, return a string matrix with one row per value,
padded with leading zeros to the width of the largest value.
<p>If <var>b</var> is a string then the characters of <var>b</var> are used as
the symbols for the digits of <var>n</var>. Space (' ') may not be used
as a symbol.
<pre class="example"> dec2base (123, "aei")
"eeeia"
</pre>
<p>The optional third argument, <var>len</var>, specifies the minimum
number of digits in the result.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>, <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- ./strings/base2dec.m -->
<p><a name="doc_002dbase2dec"></a>
<div class="defun">
— Function File: <b>base2dec</b> (<var>s, b</var>)<var><a name="index-base2dec-340"></a></var><br>
<blockquote><p>Convert <var>s</var> from a string of digits of base <var>b</var> into an
integer.
<pre class="example"> base2dec ("11120", 3)
123
</pre>
<p>If <var>s</var> is a matrix, returns a column vector with one value per
row of <var>s</var>. If a row contains invalid symbols then the
corresponding value will be NaN. Rows are right-justified before
converting so that trailing spaces are ignored.
<p>If <var>b</var> is a string, the characters of <var>b</var> are used as the
symbols for the digits of <var>s</var>. Space (' ') may not be used as a
symbol.
<pre class="example"> base2dec ("yyyzx", "xyz")
123
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>, <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- ./DLD-FUNCTIONS/hex2num.cc -->
<p><a name="doc_002dnum2hex"></a>
<div class="defun">
— Loadable Function: <var>s</var> = <b>num2hex</b> (<var>n</var>)<var><a name="index-num2hex-341"></a></var><br>
<blockquote><p>Typecast a double precision number or vector to a 16 character hexadecimal
string of the IEEE 754 representation of the number. For example
<pre class="example"> num2hex ([-1, 1, e, Inf, NaN, NA]);
"bff0000000000000
3ff0000000000000
4005bf0a8b145769
7ff0000000000000
fff8000000000000
7ff00000000007a2"
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dhex2num.html#doc_002dhex2num">hex2num</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- ./DLD-FUNCTIONS/hex2num.cc -->
<p><a name="doc_002dhex2num"></a>
<div class="defun">
— Loadable Function: <var>n</var> = <b>hex2num</b> (<var>s</var>)<var><a name="index-hex2num-342"></a></var><br>
<blockquote><p>Typecast the 16 character hexadecimal character matrix to an IEEE 754
double precision number. If fewer than 16 characters are given the
strings are right padded with '0' characters.
<p>Given a string matrix, <code>hex2num</code> treats each row as a separate
number.
<pre class="example"> hex2num (["4005bf0a8b145769";"4024000000000000"])
[2.7183; 10.000]
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dnum2hex.html#doc_002dnum2hex">num2hex</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>, <a href="doc_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- ./strings/str2double.m -->
<p><a name="doc_002dstr2double"></a>
<div class="defun">
— Function File: [<var>num</var>, <var>status</var>, <var>strarray</var>] = <b>str2double</b> (<var>str, cdelim, rdelim, ddelim</var>)<var><a name="index-str2double-343"></a></var><br>
<blockquote><p>Convert strings into numeric values.
<p><code>str2double</code> can replace <code>str2num</code>, but avoids the use of
<code>eval</code> on unknown data.
<p><var>str</var> can be the form ‘<samp><span class="samp">[+-]d[.]dd[[eE][+-]ddd]</span></samp>’ in which
‘<samp><span class="samp">d</span></samp>’ can be any of digit from 0 to 9, and ‘<samp><span class="samp">[]</span></samp>’ indicate
optional elements.
<p><var>num</var> is the corresponding numeric value. If the conversion
fails, status is -1 and <var>num</var> is NaN.
<p><var>status</var> is 0 if the conversion was successful and -1 otherwise.
<p><var>strarray</var> is a cell array of strings.
<p>Elements which are not defined or not valid return NaN and the
<var>status</var> becomes -1.
<p>If <var>str</var> is a character array or a cell array of strings, then
<var>num</var> and <var>status</var> return matrices of appropriate size.
<p><var>str</var> can also contain multiple elements separated by row and
column delimiters (<var>cdelim</var> and <var>rdelim</var>).
<p>The parameters <var>cdelim</var>, <var>rdelim</var>, and <var>ddelim</var> are
optional column, row, and decimal delimiters.
<p>The default row-delimiters are newline, carriage return and semicolon
(ASCII 10, 13 and 59). The default column-delimiters are tab, space
and comma (ASCII 9, 32, and 44). The default decimal delimiter is
‘<samp><span class="samp">.</span></samp>’ (ASCII 46).
<p><var>cdelim</var>, <var>rdelim</var>, and <var>ddelim</var> must contain only nul,
newline, carriage return, semicolon, colon, slash, tab, space, comma,
or ‘<samp><span class="samp">()[]{}</span></samp>’ (ASCII 0, 9, 10, 11, 12, 13, 14, 32, 33, 34, 40,
41, 44, 47, 58, 59, 91, 93, 123, 124, 125).
<p>Examples:
<pre class="example"> str2double ("-.1e-5")
-1.0000e-006
str2double (".314e1, 44.44e-1, .7; -1e+1")
3.1400 4.4440 0.7000
-10.0000 NaN NaN
line = "200, 300, NaN, -inf, yes, no, 999, maybe, NaN";
[x, status] = str2double (line)
x =
200 300 NaN -Inf NaN NaN 999 NaN NaN
status =
0 0 0 0 -1 -1 0 -1 0
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dstr2num.html#doc_002dstr2num">str2num</a>.
</p></blockquote></div>
<!-- ./strings/strjust.m -->
<p><a name="doc_002dstrjust"></a>
<div class="defun">
— Function File: <b>strjust</b> (<var>s, </var>[<var>"left"|"right"|"center"</var>])<var><a name="index-strjust-344"></a></var><br>
<blockquote><p>Shift the non-blank text of <var>s</var> to the left, right or center of
the string. If <var>s</var> is a string array, justify each string in the
array. Null characters are replaced by blanks. If no justification
is specified, then all rows are right-justified. For example:
<pre class="example"> strjust (["a"; "ab"; "abc"; "abcd"])
ans =
a
ab
abc
abcd
</pre>
</blockquote></div>
<!-- ./strings/str2num.m -->
<p><a name="doc_002dstr2num"></a>
<div class="defun">
— Function File: <b>str2num</b> (<var>s</var>)<var><a name="index-str2num-345"></a></var><br>
<blockquote><p>Convert the string (or character array) <var>s</var> to a number (or an
array). Examples:
<pre class="example"> str2num("3.141596")
3.141596
str2num(["1, 2, 3"; "4, 5, 6"]);
ans =
1 2 3
4 5 6
</pre>
<p><strong>Caution:</strong> As <code>str2num</code> uses the <code>eval</code> function
to do the conversion, <code>str2num</code> will execute any code contained
in the string <var>s</var>. Use <code>str2double</code> instead if you want to
avoid the use of <code>eval</code>.
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dstr2double.html#doc_002dstr2double">str2double</a>, <a href="doc_002deval.html#doc_002deval">eval</a>.
</p></blockquote></div>
<!-- mappers.cc -->
<p><a name="doc_002dtoascii"></a>
<div class="defun">
— Mapping Function: <b>toascii</b> (<var>s</var>)<var><a name="index-toascii-346"></a></var><br>
<blockquote><p>Return ASCII representation of <var>s</var> in a matrix. For example,
<pre class="example"> toascii ("ASCII")
[ 65, 83, 67, 73, 73 ]
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dchar.html#doc_002dchar">char</a>.
</p></blockquote></div>
<!-- mappers.cc -->
<p><a name="doc_002dtolower"></a>
<div class="defun">
— Mapping Function: <b>tolower</b> (<var>s</var>)<var><a name="index-tolower-347"></a></var><br>
— Mapping Function: <b>lower</b> (<var>s</var>)<var><a name="index-lower-348"></a></var><br>
<blockquote><p>Return a copy of the string or cell string <var>s</var>, with each upper-case
character replaced by the corresponding lower-case one; non-alphabetic
characters are left unchanged. For example,
<pre class="example"> tolower ("MiXeD cAsE 123")
"mixed case 123"
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dtoupper.html#doc_002dtoupper">toupper</a>.
</p></blockquote></div>
<!-- mappers.cc -->
<p><a name="doc_002dtoupper"></a>
<div class="defun">
— Built-in Function: <b>toupper</b> (<var>s</var>)<var><a name="index-toupper-349"></a></var><br>
— Built-in Function: <b>upper</b> (<var>s</var>)<var><a name="index-upper-350"></a></var><br>
<blockquote><p>Return a copy of the string or cell string <var>s</var>, with each lower-case
character replaced by the corresponding upper-case one; non-alphabetic
characters are left unchanged. For example,
<pre class="example"> toupper ("MiXeD cAsE 123")
"MIXED CASE 123"
</pre>
<!-- Texinfo @sp should work but in practice produces ugly results for HTML. -->
<!-- A simple blank line produces the correct behavior. -->
<!-- @sp 1 -->
<p class="noindent"><strong>See also:</strong> <a href="doc_002dtolower.html#doc_002dtolower">tolower</a>.
</p></blockquote></div>
<!-- utils.cc -->
<p><a name="doc_002ddo_005fstring_005fescapes"></a>
<div class="defun">
— Built-in Function: <b>do_string_escapes</b> (<var>string</var>)<var><a name="index-do_005fstring_005fescapes-351"></a></var><br>
<blockquote><p>Convert special characters in <var>string</var> to their escaped forms.
</p></blockquote></div>
<!-- utils.cc -->
<p><a name="doc_002dundo_005fstring_005fescapes"></a>
<div class="defun">
— Built-in Function: <b>undo_string_escapes</b> (<var>s</var>)<var><a name="index-undo_005fstring_005fescapes-352"></a></var><br>
<blockquote><p>Converts special characters in strings back to their escaped forms. For
example, the expression
<pre class="example"> bell = "\a";
</pre>
<p class="noindent">assigns the value of the alert character (control-g, ASCII code 7) to
the string variable <code>bell</code>. If this string is printed, the
system will ring the terminal bell (if it is possible). This is
normally the desired outcome. However, sometimes it is useful to be
able to print the original representation of the string, with the
special characters replaced by their escape sequences. For example,
<pre class="example"> octave:13> undo_string_escapes (bell)
ans = \a
</pre>
<p class="noindent">replaces the unprintable alert character with its printable
representation.
</p></blockquote></div>
</body></html>
|
