<html lang="en">
<head>
<title>PACK - The GNU Fortran Compiler</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="The GNU Fortran Compiler">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="up" href="Intrinsic-Procedures.html#Intrinsic-Procedures" title="Intrinsic Procedures">
<link rel="prev" href="OR.html#OR" title="OR">
<link rel="next" href="PARITY.html#PARITY" title="PARITY">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Funding Free Software'', the Front-Cover
Texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below). A copy of the license is included in the section entitled
``GNU Free Documentation License''.
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.-->
<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">
<a name="PACK"></a>
<p>
Next: <a rel="next" accesskey="n" href="PARITY.html#PARITY">PARITY</a>,
Previous: <a rel="previous" accesskey="p" href="OR.html#OR">OR</a>,
Up: <a rel="up" accesskey="u" href="Intrinsic-Procedures.html#Intrinsic-Procedures">Intrinsic Procedures</a>
<hr>
</div>
<h3 class="section">8.186 <code>PACK</code> — Pack an array into an array of rank one</h3>
<p><a name="index-PACK-902"></a><a name="index-array_002c-packing-903"></a><a name="index-array_002c-reduce-dimension-904"></a><a name="index-array_002c-gather-elements-905"></a>
<dl>
<dt><em>Description</em>:<dd>Stores the elements of <var>ARRAY</var> in an array of rank one.
<p>The beginning of the resulting array is made up of elements whose <var>MASK</var>
equals <code>TRUE</code>. Afterwards, positions are filled with elements taken from
<var>VECTOR</var>.
<br><dt><em>Standard</em>:<dd>Fortran 95 and later
<br><dt><em>Class</em>:<dd>Transformational function
<br><dt><em>Syntax</em>:<dd><code>RESULT = PACK(ARRAY, MASK[,VECTOR]</code>
<br><dt><em>Arguments</em>:<dd>
<p><table summary=""><tr align="left"><td valign="top" width="15%"><var>ARRAY</var> </td><td valign="top" width="70%">Shall be an array of any type.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>MASK</var> </td><td valign="top" width="70%">Shall be an array of type <code>LOGICAL</code> and
of the same size as <var>ARRAY</var>. Alternatively, it may be a <code>LOGICAL</code>
scalar.
<br></td></tr><tr align="left"><td valign="top" width="15%"><var>VECTOR</var> </td><td valign="top" width="70%">(Optional) shall be an array of the same type
as <var>ARRAY</var> and of rank one. If present, the number of elements in
<var>VECTOR</var> shall be equal to or greater than the number of true elements
in <var>MASK</var>. If <var>MASK</var> is scalar, the number of elements in
<var>VECTOR</var> shall be equal to or greater than the number of elements in
<var>ARRAY</var>.
<br></td></tr></table>
<br><dt><em>Return value</em>:<dd>The result is an array of rank one and the same type as that of <var>ARRAY</var>.
If <var>VECTOR</var> is present, the result size is that of <var>VECTOR</var>, the
number of <code>TRUE</code> values in <var>MASK</var> otherwise.
<br><dt><em>Example</em>:<dd>Gathering nonzero elements from an array:
<pre class="smallexample"> PROGRAM test_pack_1
INTEGER :: m(6)
m = (/ 1, 0, 0, 0, 5, 0 /)
WRITE(*, FMT="(6(I0, ' '))") pack(m, m /= 0) ! "1 5"
END PROGRAM
</pre>
<p>Gathering nonzero elements from an array and appending elements from <var>VECTOR</var>:
<pre class="smallexample"> PROGRAM test_pack_2
INTEGER :: m(4)
m = (/ 1, 0, 0, 2 /)
WRITE(*, FMT="(4(I0, ' '))") pack(m, m /= 0, (/ 0, 0, 3, 4 /)) ! "1 2 3 4"
END PROGRAM
</pre>
<br><dt><em>See also</em>:<dd><a href="UNPACK.html#UNPACK">UNPACK</a>
</dl>
</body></html>
