<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Comparison Ops (GNU Octave (version 5.1.0))</title> <meta name="description" content="Comparison Ops (GNU Octave (version 5.1.0))"> <meta name="keywords" content="Comparison Ops (GNU Octave (version 5.1.0))"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Expressions.html#Expressions" rel="up" title="Expressions"> <link href="Boolean-Expressions.html#Boolean-Expressions" rel="next" title="Boolean Expressions"> <link href="Arithmetic-Ops.html#Arithmetic-Ops" rel="prev" title="Arithmetic Ops"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} 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.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> <link rel="stylesheet" type="text/css" href="octave.css"> </head> <body lang="en"> <a name="Comparison-Ops"></a> <div class="header"> <p> Next: <a href="Boolean-Expressions.html#Boolean-Expressions" accesskey="n" rel="next">Boolean Expressions</a>, Previous: <a href="Arithmetic-Ops.html#Arithmetic-Ops" accesskey="p" rel="prev">Arithmetic Ops</a>, Up: <a href="Expressions.html#Expressions" accesskey="u" rel="up">Expressions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> <hr> <a name="Comparison-Operators"></a> <h3 class="section">8.4 Comparison Operators</h3> <a name="index-comparison-expressions"></a> <a name="index-expressions_002c-comparison"></a> <a name="index-relational-operators"></a> <a name="index-operators_002c-relational"></a> <a name="index-less-than-operator"></a> <a name="index-greater-than-operator"></a> <a name="index-equality-operator"></a> <a name="index-tests-for-equality"></a> <a name="index-equality_002c-tests-for"></a> <p><em>Comparison operators</em> compare numeric values for relationships such as equality. They are written using <em>relational operators</em>. </p> <p>All of Octave’s comparison operators return a value of 1 if the comparison is true, or 0 if it is false. For matrix values, they all work on an element-by-element basis. Broadcasting rules apply. See <a href="Broadcasting.html#Broadcasting">Broadcasting</a>. For example: </p> <div class="example"> <pre class="example">[1, 2; 3, 4] == [1, 3; 2, 4] ⇒ 1 0 0 1 </pre></div> <p>According to broadcasting rules, if one operand is a scalar and the other is a matrix, the scalar is compared to each element of the matrix in turn, and the result is the same size as the matrix. </p> <dl compact="compact"> <dt><code><var>x</var> < <var>y</var></code></dt> <dd><a name="index-_003c"></a> <p>True if <var>x</var> is less than <var>y</var>. </p> </dd> <dt><code><var>x</var> <= <var>y</var></code></dt> <dd><a name="index-_003c_003d"></a> <p>True if <var>x</var> is less than or equal to <var>y</var>. </p> </dd> <dt><code><var>x</var> == <var>y</var></code></dt> <dd><a name="index-_003d_003d"></a> <p>True if <var>x</var> is equal to <var>y</var>. </p> </dd> <dt><code><var>x</var> >= <var>y</var></code></dt> <dd><a name="index-_003e_003d"></a> <p>True if <var>x</var> is greater than or equal to <var>y</var>. </p> </dd> <dt><code><var>x</var> > <var>y</var></code></dt> <dd><a name="index-_003e"></a> <p>True if <var>x</var> is greater than <var>y</var>. </p> </dd> <dt><code><var>x</var> != <var>y</var></code></dt> <dt><code><var>x</var> ~= <var>y</var></code></dt> <dd><a name="index-_0021_003d"></a> <a name="index-_007e_003d"></a> <p>True if <var>x</var> is not equal to <var>y</var>. </p></dd> </dl> <p>For complex numbers, the following ordering is defined: <var>z1</var> < <var>z2</var> if and only if </p> <div class="example"> <pre class="example"> abs (<var>z1</var>) < abs (<var>z2</var>) || (abs (<var>z1</var>) == abs (<var>z2</var>) && arg (<var>z1</var>) < arg (<var>z2</var>)) </pre></div> <p>This is consistent with the ordering used by <em>max</em>, <em>min</em> and <em>sort</em>, but is not consistent with <small>MATLAB</small>, which only compares the real parts. </p> <p>String comparisons may also be performed with the <code>strcmp</code> function, not with the comparison operators listed above. See <a href="Strings.html#Strings">Strings</a>. </p> <a name="index-_003d_003d-1"></a> <a name="XREFeq"></a><dl> <dt><a name="index-eq"></a><em></em> <strong>eq</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>Return true if the two inputs are equal. </p> <p>This function is equivalent to <code><var>x</var> == <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFne">ne</a>, <a href="#XREFisequal">isequal</a>, <a href="#XREFle">le</a>, <a href="#XREFge">ge</a>, <a href="#XREFgt">gt</a>, <a href="#XREFne">ne</a>, <a href="#XREFlt">lt</a>. </p></dd></dl> <a name="index-_003e_003d-1"></a> <a name="XREFge"></a><dl> <dt><a name="index-ge"></a><em></em> <strong>ge</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>This function is equivalent to <code><var>x</var> >= <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFle">le</a>, <a href="#XREFeq">eq</a>, <a href="#XREFgt">gt</a>, <a href="#XREFne">ne</a>, <a href="#XREFlt">lt</a>. </p></dd></dl> <a name="index-_003e-1"></a> <a name="XREFgt"></a><dl> <dt><a name="index-gt"></a><em></em> <strong>gt</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>This function is equivalent to <code><var>x</var> > <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFle">le</a>, <a href="#XREFeq">eq</a>, <a href="#XREFge">ge</a>, <a href="#XREFne">ne</a>, <a href="#XREFlt">lt</a>. </p></dd></dl> <a name="XREFisequal"></a><dl> <dt><a name="index-isequal"></a><em></em> <strong>isequal</strong> <em>(<var>x1</var>, <var>x2</var>, …)</em></dt> <dd><p>Return true if all of <var>x1</var>, <var>x2</var>, … are equal. </p> <p><strong>See also:</strong> <a href="#XREFisequaln">isequaln</a>. </p></dd></dl> <a name="XREFisequaln"></a><dl> <dt><a name="index-isequaln"></a><em></em> <strong>isequaln</strong> <em>(<var>x1</var>, <var>x2</var>, …)</em></dt> <dd><p>Return true if all of <var>x1</var>, <var>x2</var>, … are equal under the additional assumption that NaN == NaN (no comparison of NaN placeholders in dataset). </p> <p><strong>See also:</strong> <a href="#XREFisequal">isequal</a>. </p></dd></dl> <a name="index-_003c_003d-1"></a> <a name="XREFle"></a><dl> <dt><a name="index-le"></a><em></em> <strong>le</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>This function is equivalent to <code><var>x</var> <= <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFeq">eq</a>, <a href="#XREFge">ge</a>, <a href="#XREFgt">gt</a>, <a href="#XREFne">ne</a>, <a href="#XREFlt">lt</a>. </p></dd></dl> <a name="index-_003c-1"></a> <a name="XREFlt"></a><dl> <dt><a name="index-lt"></a><em></em> <strong>lt</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>This function is equivalent to <code><var>x</var> < <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFle">le</a>, <a href="#XREFeq">eq</a>, <a href="#XREFge">ge</a>, <a href="#XREFgt">gt</a>, <a href="#XREFne">ne</a>. </p></dd></dl> <a name="index-_0021_003d-1"></a> <a name="index-_007e_003d-1"></a> <a name="XREFne"></a><dl> <dt><a name="index-ne"></a><em></em> <strong>ne</strong> <em>(<var>x</var>, <var>y</var>)</em></dt> <dd><p>Return true if the two inputs are not equal. </p> <p>This function is equivalent to <code><var>x</var> != <var>y</var></code><!-- /@w -->. </p> <p><strong>See also:</strong> <a href="#XREFeq">eq</a>, <a href="#XREFisequal">isequal</a>, <a href="#XREFle">le</a>, <a href="#XREFge">ge</a>, <a href="#XREFlt">lt</a>. </p></dd></dl> <hr> <div class="header"> <p> Next: <a href="Boolean-Expressions.html#Boolean-Expressions" accesskey="n" rel="next">Boolean Expressions</a>, Previous: <a href="Arithmetic-Ops.html#Arithmetic-Ops" accesskey="p" rel="prev">Arithmetic Ops</a>, Up: <a href="Expressions.html#Expressions" accesskey="u" rel="up">Expressions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> </body> </html>