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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>
<!-- ./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.
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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_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.
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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_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.
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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_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.
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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_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.
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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_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>
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<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>
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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>
<!-- ./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>
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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>
<!-- ./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>
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<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>.
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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>
<!-- 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>
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<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>
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<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>
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<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>
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