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<a name="String-Conversions"></a>
<p>
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>
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<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>
<!-- bin2dec scripts/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-396"></a></var><br>
<blockquote><p>Return the decimal number corresponding to the binary number represented
by the string <var>s</var>. For example:
<pre class="example"> bin2dec ("1110")
⇒ 14
</pre>
<p>Spaces are ignored during conversion and may be used to make the binary
number more readable.
<pre class="example"> bin2dec ("1000 0001")
⇒ 129
</pre>
<p>If <var>s</var> is a string matrix, return a column vector with one converted
number per row of <var>s</var>; Invalid rows evaluate to NaN.
<p>If <var>s</var> is a cell array of strings, return a column vector with one
converted number per cell element in <var>s</var>.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>, <a href="doc_002dbase2dec.html#doc_002dbase2dec">base2dec</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>.
</p></blockquote></div>
<!-- dec2bin scripts/strings/dec2bin.m -->
<p><a name="doc_002ddec2bin"></a>
<div class="defun">
— Function File: <b>dec2bin</b> (<var>d, len</var>)<var><a name="index-dec2bin-397"></a></var><br>
<blockquote><p>Return a binary number corresponding to the non-negative integer
<var>d</var>, as a string of ones and zeros. For example:
<pre class="example"> dec2bin (14)
⇒ "1110"
</pre>
<p>If <var>d</var> is a matrix or cell array, return a string matrix with one
row per element in <var>d</var>, 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.
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<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_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- dec2hex scripts/strings/dec2hex.m -->
<p><a name="doc_002ddec2hex"></a>
<div class="defun">
— Function File: <b>dec2hex</b> (<var>d, len</var>)<var><a name="index-dec2hex-398"></a></var><br>
<blockquote><p>Return the hexadecimal string corresponding to the non-negative
integer <var>d</var>. For example:
<pre class="example"> dec2hex (2748)
⇒ "ABC"
</pre>
<p>If <var>d</var> is a matrix or cell array, return a string matrix with one
row per element in <var>d</var>, 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.
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<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_002ddec2bin.html#doc_002ddec2bin">dec2bin</a>.
</p></blockquote></div>
<!-- hex2dec scripts/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-399"></a></var><br>
<blockquote><p>Return the integer corresponding to the hexadecimal number represented
by 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, return a column vector with one converted
number per row of <var>s</var>; Invalid rows evaluate to NaN.
<p>If <var>s</var> is a cell array of strings, return a column vector with one
converted number per cell element in <var>s</var>.
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<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_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>.
</p></blockquote></div>
<!-- dec2base scripts/strings/dec2base.m -->
<p><a name="doc_002ddec2base"></a>
<div class="defun">
— Function File: <b>dec2base</b> (<var>d, base</var>)<var><a name="index-dec2base-400"></a></var><br>
— Function File: <b>dec2base</b> (<var>d, base, len</var>)<var><a name="index-dec2base-401"></a></var><br>
<blockquote><p>Return a string of symbols in base <var>base</var> corresponding to
the non-negative integer <var>d</var>.
<pre class="example"> dec2base (123, 3)
⇒ "11120"
</pre>
<p>If <var>d</var> is a matrix or cell array, return a string matrix with one
row per element in <var>d</var>, padded with leading zeros to the width of
the largest value.
<p>If <var>base</var> is a string then the characters of <var>base</var> are used as
the symbols for the digits of <var>d</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.
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<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_002ddec2hex.html#doc_002ddec2hex">dec2hex</a>.
</p></blockquote></div>
<!-- base2dec scripts/strings/base2dec.m -->
<p><a name="doc_002dbase2dec"></a>
<div class="defun">
— Function File: <b>base2dec</b> (<var>s, base</var>)<var><a name="index-base2dec-402"></a></var><br>
<blockquote><p>Convert <var>s</var> from a string of digits in base <var>base</var> to a decimal
integer (base 10).
<pre class="example"> base2dec ("11120", 3)
⇒ 123
</pre>
<p>If <var>s</var> is a string matrix, return 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.
<p>If <var>s</var> is a cell array of strings, return a column vector with one
value per cell element in <var>s</var>.
<p>If <var>base</var> is a string, the characters of <var>base</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>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddec2base.html#doc_002ddec2base">dec2base</a>, <a href="doc_002dbin2dec.html#doc_002dbin2dec">bin2dec</a>, <a href="doc_002dhex2dec.html#doc_002dhex2dec">hex2dec</a>.
</p></blockquote></div>
<!-- num2hex src/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-403"></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>
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<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>
<!-- hex2num src/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-404"></a></var><br>
<blockquote><p>Typecast the 16 character hexadecimal character string 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>
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<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>
<!-- str2double src/DLD-FUNCTIONS/str2double.cc -->
<p><a name="doc_002dstr2double"></a>
<div class="defun">
— Built-in Function: <b>str2double</b> (<var>s</var>)<var><a name="index-str2double-405"></a></var><br>
<blockquote><p>Convert a string to a real or complex number.
<p>The string must be in one of the following formats where
a and b are real numbers and the complex unit is 'i' or 'j':
<ul>
<li>a + bi
<li>a + b*i
<li>a + i*b
<li>bi + a
<li>b*i + a
<li>i*b + a
</ul>
<p>If present, a and/or b are of the form [+-]d[,.]d[[eE][+-]d] where
the brackets indicate optional arguments and 'd' indicates zero or more
digits. The special input values <code>Inf</code>, <code>NaN</code>, and <code>NA</code> are
also accepted.
<p><var>s</var> may also be a character matrix, in which case the conversion is
repeated for each row. Or <var>s</var> may be a cell array of strings, in which
case each element is converted and an array of the same dimensions is
returned.
<p><code>str2double</code> returns NaN for elements of <var>s</var> which cannot be
converted.
<p><code>str2double</code> can replace <code>str2num</code>, and it avoids the security
risk of using <code>eval</code> on unknown data.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dstr2num.html#doc_002dstr2num">str2num</a>.
</p></blockquote></div>
<!-- strjust scripts/strings/strjust.m -->
<p><a name="doc_002dstrjust"></a>
<div class="defun">
— Function File: <b>strjust</b> (<var>s</var>)<var><a name="index-strjust-406"></a></var><br>
— Function File: <b>strjust</b> (<var>s, pos</var>)<var><a name="index-strjust-407"></a></var><br>
<blockquote><p>Return the text, <var>s</var>, justified according to <var>pos</var>, which may
be ‘<samp><span class="samp">"left"</span></samp>’, ‘<samp><span class="samp">"center"</span></samp>’, or ‘<samp><span class="samp">"right"</span></samp>’. If <var>pos</var>
is omitted it defaults to ‘<samp><span class="samp">"right"</span></samp>’.
<p>Null characters are replaced by spaces. All other character
data are treated as non-white space.
<p>Example:
<pre class="example"> strjust (["a"; "ab"; "abc"; "abcd"])
⇒
" a"
" ab"
" abc"
"abcd"
</pre>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002ddeblank.html#doc_002ddeblank">deblank</a>, <a href="doc_002dstrrep.html#doc_002dstrrep">strrep</a>, <a href="doc_002dstrtrim.html#doc_002dstrtrim">strtrim</a>, <a href="doc_002duntabify.html#doc_002duntabify">untabify</a>.
</p></blockquote></div>
<!-- str2num scripts/strings/str2num.m -->
<p><a name="doc_002dstr2num"></a>
<div class="defun">
— Function File: <var>x</var> = <b>str2num</b> (<var>s</var>)<var><a name="index-str2num-408"></a></var><br>
— Function File: [<var>x</var>, <var>state</var>] = <b>str2num</b> (<var>s</var>)<var><a name="index-str2num-409"></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"])
⇒ 1 2 3
4 5 6
</pre>
<p>The optional second output, <var>state</var>, is logically true when the
conversion is successful. If the conversion fails the numeric output,
<var>x</var>, is empty and <var>state</var> is false.
<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> for a safer and faster
conversion.
<p>For cell array of strings use <code>str2double</code>.
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<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>
<!-- toascii src/mappers.cc -->
<p><a name="doc_002dtoascii"></a>
<div class="defun">
— Mapping Function: <b>toascii</b> (<var>s</var>)<var><a name="index-toascii-410"></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>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dchar.html#doc_002dchar">char</a>.
</p></blockquote></div>
<!-- tolower src/mappers.cc -->
<p><a name="doc_002dtolower"></a>
<div class="defun">
— Mapping Function: <b>tolower</b> (<var>s</var>)<var><a name="index-tolower-411"></a></var><br>
— Mapping Function: <b>lower</b> (<var>s</var>)<var><a name="index-lower-412"></a></var><br>
<blockquote><p>Return a copy of the string or cell string <var>s</var>, with each uppercase
character replaced by the corresponding lowercase one; non-alphabetic
characters are left unchanged. For example:
<pre class="example"> tolower ("MiXeD cAsE 123")
⇒ "mixed case 123"
</pre>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dtoupper.html#doc_002dtoupper">toupper</a>.
</p></blockquote></div>
<!-- toupper src/mappers.cc -->
<p><a name="doc_002dtoupper"></a>
<div class="defun">
— Mapping Function: <b>toupper</b> (<var>s</var>)<var><a name="index-toupper-413"></a></var><br>
— Mapping Function: <b>upper</b> (<var>s</var>)<var><a name="index-upper-414"></a></var><br>
<blockquote><p>Return a copy of the string or cell string <var>s</var>, with each lowercase
character replaced by the corresponding uppercase one; non-alphabetic
characters are left unchanged. For example:
<pre class="example"> toupper ("MiXeD cAsE 123")
⇒ "MIXED CASE 123"
</pre>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dtolower.html#doc_002dtolower">tolower</a>.
</p></blockquote></div>
<!-- do_string_escapes src/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-415"></a></var><br>
<blockquote><p>Convert special characters in <var>string</var> to their escaped forms.
</p></blockquote></div>
<!-- undo_string_escapes src/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-416"></a></var><br>
<blockquote><p>Convert 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>
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