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<title>Conversion of Numerical Data to Strings - GNU Octave</title>
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<a name="Conversion-of-Numerical-Data-to-Strings"></a>
<p>
Previous: <a rel="previous" accesskey="p" href="Concatenating-Strings.html#Concatenating-Strings">Concatenating Strings</a>,
Up: <a rel="up" accesskey="u" href="Creating-Strings.html#Creating-Strings">Creating Strings</a>
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<h4 class="subsection">5.3.2 Conversion of Numerical Data to Strings</h4>
<p>Apart from the string concatenation functions (see <a href="Concatenating-Strings.html#Concatenating-Strings">Concatenating Strings</a>)
which cast numerical data to the corresponding ASCII characters, there are
several functions that format numerical data as strings. <code>mat2str</code> and
<code>num2str</code> convert real or complex matrices, while <code>int2str</code> converts
integer matrices. <code>int2str</code> takes the real part of complex values and
round fractional values to integer. A more flexible way to format numerical
data as strings is the <code>sprintf</code> function (see <a href="Formatted-Output.html#Formatted-Output">Formatted Output</a>,
<a href="doc_002dsprintf.html#doc_002dsprintf">doc-sprintf</a>).
<!-- mat2str scripts/strings/mat2str.m -->
<p><a name="doc_002dmat2str"></a>
<div class="defun">
— Function File: <var>s</var> = <b>mat2str</b> (<var>x, n</var>)<var><a name="index-mat2str-343"></a></var><br>
— Function File: <var>s</var> = <b>mat2str</b> (<var>x, n, "class"</var>)<var><a name="index-mat2str-344"></a></var><br>
<blockquote><p>Format real, complex, and logical matrices as strings. The
returned string may be used to reconstruct the original matrix by using
the <code>eval</code> function.
<p>The precision of the values is given by <var>n</var>. If <var>n</var> is a
scalar then both real and imaginary parts of the matrix are printed
to the same precision. Otherwise <var>n</var><code>(1)</code> defines the
precision of the real part and <var>n</var><code>(2)</code> defines the
precision of the imaginary part. The default for <var>n</var> is 15.
<p>If the argument "class" is given then the class of <var>x</var> is
included in the string in such a way that <code>eval</code> will result in the
construction of a matrix of the same class.
<pre class="example"> mat2str ([ -1/3 + i/7; 1/3 - i/7 ], [4 2])
⇒ "[-0.3333+0.14i;0.3333-0.14i]"
mat2str ([ -1/3 +i/7; 1/3 -i/7 ], [4 2])
⇒ "[-0.3333+0i 0+0.14i;0.3333+0i -0-0.14i]"
mat2str (int16([1 -1]), "class")
⇒ "int16([1 -1])"
mat2str (logical (eye (2)))
⇒ "[true false;false true]"
isequal (x, eval (mat2str (x)))
⇒ 1
</pre>
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dsprintf.html#doc_002dsprintf">sprintf</a>, <a href="doc_002dnum2str.html#doc_002dnum2str">num2str</a>, <a href="doc_002dint2str.html#doc_002dint2str">int2str</a>.
</p></blockquote></div>
<!-- num2str scripts/general/num2str.m -->
<p><a name="doc_002dnum2str"></a>
<div class="defun">
— Function File: <b>num2str</b> (<var>x</var>)<var><a name="index-num2str-345"></a></var><br>
— Function File: <b>num2str</b> (<var>x, precision</var>)<var><a name="index-num2str-346"></a></var><br>
— Function File: <b>num2str</b> (<var>x, format</var>)<var><a name="index-num2str-347"></a></var><br>
<blockquote><p>Convert a number (or array) to a string (or a character array). The
optional second argument may either give the number of significant
digits (<var>precision</var>) to be used in the output or a format
template string (<var>format</var>) as in <code>sprintf</code> (see <a href="Formatted-Output.html#Formatted-Output">Formatted Output</a>). <code>num2str</code> can also handle complex numbers. For
example:
<pre class="example"> num2str (123.456)
⇒ "123.46"
num2str (123.456, 4)
⇒ "123.5"
s = num2str ([1, 1.34; 3, 3.56], "%5.1f")
⇒ s =
1.0 1.3
3.0 3.6
whos s
⇒
Attr Name Size Bytes Class
==== ==== ==== ===== =====
s 2x8 16 char
num2str (1.234 + 27.3i)
⇒ "1.234+27.3i"
</pre>
<p>The <code>num2str</code> function is not very flexible. For better control
over the results, use <code>sprintf</code> (see <a href="Formatted-Output.html#Formatted-Output">Formatted Output</a>).
Note that for complex <var>x</var>, the format string may only contain one
output conversion specification and nothing else. Otherwise, you
will get unpredictable results.
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dsprintf.html#doc_002dsprintf">sprintf</a>, <a href="doc_002dint2str.html#doc_002dint2str">int2str</a>, <a href="doc_002dmat2str.html#doc_002dmat2str">mat2str</a>.
</p></blockquote></div>
<!-- int2str scripts/general/int2str.m -->
<p><a name="doc_002dint2str"></a>
<div class="defun">
— Function File: <b>int2str</b> (<var>n</var>)<var><a name="index-int2str-348"></a></var><br>
<blockquote><p>Convert an integer (or array of integers) to a string (or a character
array).
<pre class="example"> int2str (123)
⇒ "123"
s = int2str ([1, 2, 3; 4, 5, 6])
⇒ s =
1 2 3
4 5 6
whos s
⇒ s =
Attr Name Size Bytes Class
==== ==== ==== ===== =====
s 2x7 14 char
</pre>
<p>This function is not very flexible. For better control over the
results, use <code>sprintf</code> (see <a href="Formatted-Output.html#Formatted-Output">Formatted Output</a>).
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<p class="noindent"><strong>See also:</strong> <a href="doc_002dsprintf.html#doc_002dsprintf">sprintf</a>, <a href="doc_002dnum2str.html#doc_002dnum2str">num2str</a>, <a href="doc_002dmat2str.html#doc_002dmat2str">mat2str</a>.
</p></blockquote></div>
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