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<reference id="ref.array">
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<title>Array functions</title>
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<titleabbrev>Arrays</titleabbrev>
<refentry id="function.array">
<refnamediv>
<refname>array</refname>
<refpurpose>
Create an array
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>array</function></funcdef>
<varargs>
</funcsynopsis>
<para>
Returns an array of the parameters. The parameters can be given
an index with the <literal>=></literal> operator.
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<note>
<para>
<function>array</function> is a language construct used to represent
literal arrays, and not a regular function.
</para>
</note>
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<para>
The following example demonstrates how to create a
two-dimensional array, how to specify keys for associative
arrays, and how to skip-and-continue numeric indices in normal
arrays.
<example>
<title><function>array</function> example</title>
<programlisting>
$fruits = array(
"fruits" => array("a"=>"orange","b"=>"banana","c"=>"apple"),
"numbers" => array(1, 2, 3, 4, 5, 6),
"holes" => array("first", 5 => "second", "third")
);
</programlisting></example>
<para>
See also:
<function>list</function>.
</refsect1>
</refentry>
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<refentry id="function.array-push">
<refnamediv>
<refname>array_push</refname>
<refpurpose>Push one or more elements onto the end of array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>int <function>array_push</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>mixed <parameter>var</parameter></paramdef>
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<paramdef><parameter><optional>...</optional></parameter></paramdef>
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</funcsynopsis>
<para>
<function>array_push</function> treats
<parameter>array</parameter> as a stack, and pushes the passed
variables onto the end of <parameter>array</parameter>. The
length of <parameter>array</parameter> increases by the number of
variables pushed. Has the same effect as:
<programlisting>
$array[] = $var;
</programlisting>
repeated for each <parameter>var</parameter>.
<para>
Returns the new number of elements in the array.
<para>
<example>
<title><function>array_push</function> example</title>
<programlisting>
$stack = array(1, 2);
array_push($stack, "+", 3);
</programlisting>
</example>
This example would result in $stack having 4 elements: 1, 2, "+", and 3.
<para>
See also <function>array_pop</function>,
<function>array_shift</function>, and
<function>array_unshift</function>.
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
<refentry id="function.array-pop">
<refnamediv>
<refname>array_pop</refname>
<refpurpose>Pop the element off the end of array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>array_pop</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
<function>array_pop</function> pops and returns the last value of
the <parameter>array</parameter>, shortening the
<parameter>array</parameter> by one element.
<para>
<example>
<title><function>array_pop</function> example</title>
<programlisting>
$stack = array("orange", "apple", "raspberry");
$fruit = array_pop($stack);
</programlisting>
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<para>
After this, $stack has only 2 elements: "orange" and "apple",
and $fruit has "raspberry".
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</example>
<para>
See also <function>array_push</function>,
<function>array_shift</function>, and
<function>array_unshift</function>.
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
<refentry id="function.array-unshift">
<refnamediv>
<refname>array_unshift</refname>
<refpurpose>Push one or more elements
onto the beginning of array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>array_unshift</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>mixed <parameter>var</parameter></paramdef>
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<paramdef><parameter><optional>...</optional></parameter></paramdef>
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</funcprototype>
</funcsynopsis>
<para>
<function>array_unshift</function> prepends passed elements to
the front of the <parameter>array</parameter>. Note that the list
of elements is prepended as a whole, so that the prepended
elements stay in the same order.
<para>
Returns the new number of elements in the
<parameter>array</parameter>.
<para>
<example>
<title><function>array_unshift</function> example</title>
<programlisting>
$queue = array("p1", "p3");
array_unshift($queue, "p4", "p5", "p6");
</programlisting>
</example>
This would result in $queue having 5 elements: "p4", "p5", "p6",
"p1", and "p3".
<para>
See also <function>array_shift</function>,
<function>array_push</function>, and
<function>array_pop</function>.
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
<refentry id="function.array-shift">
<refnamediv>
<refname>array_shift</refname>
<refpurpose>Pop an element of the beginning of array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>array_shift</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
<function>array_shift</function> shifts the first value of the
<parameter>array</parameter> off and returns it, shortening the
<parameter>array</parameter> by one element and moving everything
down.
<para>
<example>
<title><function>array_shift</function> example</title>
<programlisting>
$args = array("-v", "-f");
$opt = array_shift($args);
</programlisting>
</example>
This would result in $args having one element "-f" left, and $opt
being "-v".
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<para>
See also <function>array_unshift</function>,
<function>array_push</function>, and
<function>array_pop</function>.
<note>
<para>
This function was added in PHP 4.0.
</note>
</refsect1>
</refentry>
<refentry id="function.array-slice">
<refnamediv>
<refname>array_slice</refname>
<refpurpose>Extract a slice of the array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>array_slice</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>int <parameter>offset</parameter></paramdef>
<paramdef>int
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<parameter>
<optional>length</optional>
</parameter>
</paramdef>
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</funcsynopsis>
<para>
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<function>array_slice</function> returns a sequence of elements
from the <parameter>array</parameter> specified by the
<parameter>offset</parameter> and <parameter>length</parameter>
parameters.
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<para>
If <parameter>offset</parameter> is positive, the sequence will
start at that offset in the <parameter>array</parameter>. If
<parameter>offset</parameter> is negative, the sequence will
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start that far from the end of the <parameter>array</parameter>.
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<para>
If <parameter>length</parameter> is given and is positive, then
the sequence will have that many elements in it. If
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<parameter>length</parameter> is given and is negative then the
sequence will stop that many elements from the end of the
array. If it is omitted, then the sequence will have everything
from <parameter>offset</parameter> up until the end of the
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<parameter>array</parameter>.
<para>
<example>
<title><function>array_slice</function> examples</title>
<programlisting>
$input = array("a", "b", "c", "d", "e");
$output = array_slice($input, 2); // returns "c", "d", and "e"
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$output = array_slice($input, 2, -1); // returns "c", "d"
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$output = array_slice($input, -2, 1); // returns "d"
$output = array_slice($input, 0, 3); // returns "a", "b", and "c"
</programlisting>
</example>
<para>
See also <function>array_splice</function>.
<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
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<refentry id="function.array-splice">
<refnamediv>
<refname>array_splice</refname>
<refpurpose>Remove a portion of the array and replace it with something else</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>array_splice</function></funcdef>
<paramdef>array <parameter>input</parameter></paramdef>
<paramdef>int <parameter>offset</parameter></paramdef>
<paramdef>int
<parameter><optional>length</optional></parameter></paramdef>
<paramdef>array
<parameter><optional>replacement</optional></parameter></paramdef>
</funcsynopsis>
<para>
<function>array_splice</function> removed the elements designated
by <parameter>offset</parameter> and
<parameter>length</parameter> from the
<parameter>input</parameter> array, and replaces them with the
elements of the <parameter>replacement</parameter> array, if supplied.
<para>
If <parameter>offset</parameter> is positive then the start of
removed portion is at that offset from the beginning of the
<parameter>input</parameter> array. If
<parameter>offset</parameter> is negative then it starts that far
from the end of the <parameter>input</parameter> array.
<para>
If <parameter>length</parameter> is omitted, removes everything
from <parameter>offset</parameter> to the end of the array. If
<parameter>length</parameter> is specified and is positive, then
that many elements will be removed. If
<parameter>length</parameter> is specified and is negative then
the end of the removed portion will be that many elements from
the end of the array. Tip: to remove everything from
<parameter>offset</parameter> to the end of the array when
<parameter>replacement</parameter> is also specified, use
<literal>count($input)</literal> for
<parameter>length</parameter>.
<para>
If <parameter>replacement</parameter> array is specified, then
the removed elements are replaced with elements from this array. If <parameter>offset</parameter> and <parameter>length</parameter> are such that nothing is removed, then the elements from the <parameter>replacement</parameter> array are inserted in the place specified by the <parameter>offset</parameter>. Tip: if the replacement is just one element it is not necessary to put <literal>array()</literal> around it, unless the element is an array itself.
<para>
The following equivalences hold:
<programlisting>
array_push($input, $x, $y) array_splice($input, count($input), 0, array($x, $y))
array_pop($input) array_splice($input, -1)
array_shift($input) array_splice($input, 0, 1)
array_unshift($input, $x, $y) array_splice($input, 0, 0, array($x, $y))
$a[$x] = $y array_splice($input, $x, 1, $y)
</programlisting>
<para>
Returns the array consisting of removed elements.
<para>
<example>
<title><function>array_splice</function> examples</title>
<programlisting>
$input = array("red", "green", "blue", "yellow");
array_splice($input, 2); // $input is now array("red", "green")
array_splice($input, 1, -1); // $input is now array("red", "yellow")
array_splice($input, 1, count($input), "orange"); // $input is now array("red", "orange")
array_splice($input, -1, 1, array("black", "maroon")); // $input is now array("red", "green", "blue", "black", "maroon")
</programlisting>
</example>
<para>
See also <function>array_slice</function>.
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
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<refentry id="function.array-keys">
<refnamediv>
<refname>array_keys</refname>
<refpurpose>Return all the keys of an array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>array_keys</function></funcdef>
<paramdef>array <parameter>input</parameter></paramdef>
</funcsynopsis>
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<para>
<function>array_keys</function> returns all the keys, numeric and string, from the <parameter>input</parameter> array.
<para>
<example>
<title><function>array_keys</function> example</title>
<programlisting>
$array = array(0 => 100, "color" => "red");
array_keys($array); // returns array(0, "color")
</programlisting>
</example>
<para>
See also <function>array_values</function>.
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
<refentry id="function.array-values">
<refnamediv>
<refname>array_values</refname>
<refpurpose>Return all the values of an array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>array_values</function></funcdef>
<paramdef>array <parameter>input</parameter></paramdef>
</funcsynopsis>
<para>
<function>array_values</function> returns all the values from the <parameter>input</parameter> array.
<para>
<example>
<title><function>array_values</function> example</title>
<programlisting>
$array = array("size" => "XL", "color" => "gold");
array_values($array); // returns array("XL", "gold")
</programlisting>
</example>
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<note>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
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<refentry id="function.array-walk">
<refnamediv>
<refname>array_walk</refname>
<refpurpose>
Apply a user function to every member of an array.
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>int <function>array_walk</function></funcdef>
<paramdef>array <parameter>arr</parameter></paramdef>
<paramdef>string <parameter>func</parameter></paramdef>
</funcsynopsis>
<simpara>
Applies the function named by <parameter>func</parameter> to each
element of <parameter>arr</parameter>. The elements are passed as
the first argument of <parameter>func</parameter>; if
<parameter>func</parameter> requires more than one argument, a
warning will be generated each time
<function>array_walk</function> calls
<parameter>func</parameter>. These warnings may be suppressed by
prepending the '@' sign to the <function>array_walk</function>
call, or by using <function>error_reporting</function>.
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<note>
<para>
<parameter>func</parameter> will actually be working with the
elements of <parameter>arr</parameter>, so any changes made to
those elements will be made in the array itself.
</para>
</note>
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<para>
<example>
<title><function>array_walk</function> example</title>
<programlisting>
$fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
function test_alter( $item1 ) {
$item1 = 'bogus';
}
function test_print( $item2 ) {
echo "$item2<br>\n";
}
array_walk( $fruits, 'test_print' );
array_walk( $fruits, 'test_alter' );
array_walk( $fruits, 'test_print' );
</programlisting>
</example>
<simpara>
See also <function>each</function> and <function>list</function>.
</refsect1>
</refentry>
<refentry id="function.arsort">
<refnamediv>
<refname>arsort</refname>
<refpurpose>
Sort an array in reverse order and maintain index association
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>arsort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
This function sorts an array such that array indices maintain their
correlation with the array elements they are associated with. This is
used mainly when sorting associative arrays where the actual element
order is significant.
<example>
<title><function>arsort</function> example</title>
<programlisting>
$fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
arsort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
}
</programlisting></example>
This example would display:
<computeroutput>
fruits[a] = orange
fruits[d] = lemon
fruits[b] = banana
fruits[c] = apple
</computeroutput>
The fruits have been sorted in reverse alphabetical order, and
the index associated with each element has been maintained.
<para>
See also: <function>asort</function>, <function>rsort</function>,
<function>ksort</function>, and <function>sort</function>.
</refsect1>
</refentry>
<refentry id="function.asort">
<refnamediv>
<refname>asort</refname>
<refpurpose>Sort an array and maintain index association</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>asort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
This function sorts an array such that array indices maintain their
correlation with the array elements they are associated with. This is
used mainly when sorting associative arrays where the actual element
order is significant.
<example>
<title><function>asort</function> example</title>
<programlisting>
$fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
asort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
}
</programlisting></example>
This example would display:
<computeroutput>
fruits[c] = apple
fruits[b] = banana
fruits[d] = lemon
fruits[a] = orange
</computeroutput>
The fruits have been sorted in alphabetical order, and the index
associated with each element has been maintained.
<para>
See also <function>arsort</function>, <function>rsort</function>,
<function>ksort</function>, and <function>sort</function>.
</refsect1>
</refentry>
<refentry id="function.count">
<refnamediv>
<refname>count</refname>
<refpurpose>count elements in a variable</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>int <function>count</function></funcdef>
<paramdef>mixed <parameter>var</parameter></paramdef>
</funcsynopsis>
<para>
Returns the number of elements in <parameter>var</parameter>, which is
typically an array (since anything else will have one element).
<para>
Returns 1 if the variable is not an array.
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<para>
Returns 0 if the variable is not set.
<warning>
<para>
<function>count</function> may return 0 for a variable that isn't
set, but it may also return 0 for a variable that has been initialized
with an empty array. Use <function>isset</function> to test if a
variable is set.
</para>
</warning>
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<para>
See also:
<function>sizeof</function>, <function>isset</function>, and
<function>is_array</function>.
</refsect1>
</refentry>
<refentry id="function.current">
<refnamediv>
<refname>current</refname>
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<refpurpose>Return the current element in an array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>current</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
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Every array has an internal pointer to its "current" element,
which is initialized to the first element inserted into the
array.
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<para>
The <function>current</function> function simply returns the
array element that's currently being pointed by the internal
pointer. It does not move the pointer in any way. If the
internal pointer points beyond the end of the elements list,
<function>current</function> returns false.
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<warning>
<para>
If the array contains empty elements (0 or "", the empty string)
then this function will return false for these elements as well.
This makes it impossible to determine if you are really at the
end of the list in such an array using <function>current</function>.
To properly traverse an array that may contain empty elements,
use the <function>each</function> function.
</warning>
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<para>
See also:
<function>end</function>, <function>next</function>,
<function>prev</function> and <function>reset</function>.
</refsect1>
</refentry>
<refentry id="function.each">
<refnamediv>
<refname>each</refname>
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<refpurpose>Return the next key and value pair from an array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>each</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
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Returns the current key and value pair from the array
<parameter>array</parameter> and advances the array
cursor. This pair is returned in a four-element array,
with the keys <emphasis>0</emphasis>, <emphasis>1</emphasis>,
<emphasis>key</emphasis>, and <emphasis>value</emphasis>. Elements
<emphasis>0</emphasis> and <emphasis>key</emphasis> contain
the key name of the array element, and <emphasis>1</emphasis>
and <emphasis>value</emphasis> contain the data.
<para>
If the internal pointer for the array points past the end of the
array contents, <function>each</function> returns false.
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<para>
<example>
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<title><function>each</function> examples</title>
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<programlisting>
$foo = array( "bob", "fred", "jussi", "jouni" );
$bar = each( $foo );
</programlisting>
<para>
<literal>$bar</literal> now contains the following key/value
pairs:
<itemizedlist spacing="compact">
<listitem><simpara>0 => 0
<listitem><simpara>1 => 'bob'
<listitem><simpara>key => 0
<listitem><simpara>value => 'bob'
</itemizedlist>
<programlisting>
$foo = array( "Robert" => "Bob", "Seppo" => "Sepi" );
$bar = each( $foo );
</programlisting>
<para>
<literal>$bar</literal> now contains the following key/value
pairs:
<itemizedlist spacing="compact">
<listitem><simpara>0 => 'Robert'
<listitem><simpara>1 => 'Bob'
<listitem><simpara>key => 'Robert'
<listitem><simpara>value => 'Bob'
</itemizedlist>
</example>
<para>
<function>each</function> is typically used in conjunction with
<function>list</function> to traverse an array; for instance,
$HTTP_POST_VARS:
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<example><title>Traversing $HTTP_POST_VARS with <function>each</function></title>
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<programlisting>
echo "Values submitted via POST method:<br>";
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while (list($key, $val) = each($HTTP_POST_VARS)) {
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echo "$key => $val<br>";
}
</programlisting>
</example>
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<para>
After <function>each</function> has executed, the array cursor
will be left on the next element of the array, or on the last
element if it hits the end of the array.
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<para>
See also <function>key</function>, <function>list</function>,
<function>current</function>, <function>reset</function>,
<function>next</function>, and <function>prev</function>.
</refsect1>
</refentry>
<refentry id="function.end">
<refnamediv>
<refname>end</refname>
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<refpurpose>Set the internal pointer of an array to its last element</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef><function>end</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
<function>end</function> advances <parameter>array</parameter>'s
internal pointer to the last element.
<para>
See also:
<function>current</function>, <function>each</function>, <function>end</function>
<function>next</function> and <function>reset</function>
</refsect1>
</refentry>
1999-07-16 21:43:06 +00:00
<refentry id="function.in-array">
<refnamediv>
<refname>in_array</refname>
<refpurpose>Check if a value exists in an array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>bool in_array</funcdef>
<paramdef>mixed <parameter>needle</parameter></paramdef>
<paramdef>array <parameter>haystack</parameter></paramdef>
</funcsynopsis>
<para>
Searches <parameter>haystack</parameter> for
<parameter>needle</parameter> and returns true if it is found in
the array, false otherwise.
<para>
<example>
<title><function>in_array</function> example</title>
<programlisting>
$os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os))
print "Got Irix";
</programlisting>
</example>
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<note>
<para>
This function was added in PHP 4.0.
</note>
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</refsect1>
</refentry>
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<refentry id="function.key">
<refnamediv>
<refname>key</refname>
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<refpurpose>Fetch a key from an associative array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>key</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
<function>key</function> returns the index element of the
current array position.
<para>
See also:
<function>current</function>,
<function>next</function>
</refsect1>
</refentry>
<refentry id="function.ksort">
<refnamediv>
<refname>ksort</refname>
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<refpurpose>Sort an array by key</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>int <function>ksort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
Sorts an array by key, maintaining key to data correlations. This
is useful mainly for associative arrays.
<example>
<title><function>ksort</function> example</title>
<programlisting>
$fruits = array("d"=>"lemon","a"=>"orange","b"=>"banana","c"=>"apple");
ksort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
}
</programlisting></example>
This example would display:
<computeroutput>
fruits[a] = orange
fruits[b] = banana
fruits[c] = apple
fruits[d] = lemon
</computeroutput>
<simpara>
See also <function>asort</function>, <function>arsort</function>,
<function>sort</function>, and <function>rsort</function>.
</refsect1>
</refentry>
<refentry id="function.list">
<refnamediv>
<refname>list</refname>
<refpurpose>
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Assign variables as if they were an array
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</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>list</function></funcdef>
<varargs>
</funcsynopsis>
<para>
Like <function>array</function>, this is not really a function,
but a language construct. <function>list</function> is used to
assign a list of variables in one operation.
<example>
<title><function>list</function> example</title>
<programlisting>
<table>
<tr>
<th>Employee name</th>
<th>Salary</th>
</tr>
<?php
$result = mysql($conn, "SELECT id, name, salary FROM employees");
while (list($id, $name, $salary) = mysql_fetch_row($result)) {
print(" <tr>\n".
" <td><a href=\"info.php3?id=$id\">$name</a></td>\n".
" <td>$salary</td>\n".
" </tr>\n");
}
?></table>
</programlisting></example>
<para>
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See also: <function>each</function>, <function>array</function>.
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</refsect1>
</refentry>
<refentry id="function.next">
<refnamediv>
<refname>next</refname>
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<refpurpose>Advance the internal array pointer of an array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>next</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
Returns the array element in the next place that's pointed by the
internal array pointer, or false if there are no more elements.
<para>
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<function>next</function> behaves like <function>current</function>,
with one difference. It advances the internal array pointer one
place forward before returning the element. That means it returns
the next array element and advances the internal array pointer by
one. If advancing the internal array pointer results in going beyond
the end of the element list, <function>next</function> returns false.
<warning>
<para>
If the array contains empty elements then this function will return
false for these elements as well. To properly traverse an array
which may contain empty elements see the <function>each</function>
function.
</para>
</warning>
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<para>
See also:
<function>current</function>, <function>end</function>
<function>prev</function> and <function>reset</function>
</refsect1>
</refentry>
<refentry id="function.pos">
<refnamediv>
<refname>pos</refname>
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<refpurpose>Get the current element from an array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>pos</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<simpara>
This is an alias for <function>current</function>.
<para>
See also:
<function>end</function>, <function>next</function>,
<function>prev</function> and <function>reset</function>.
</refsect1>
</refentry>
<refentry id="function.prev">
<refnamediv>
<refname>prev</refname>
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<refpurpose>Rewind the internal array pointer</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>prev</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
Returns the array element in the previous place that's pointed by
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the internal array pointer, or false if there are no more elements.
<warning>
<para>
If the array contains empty elements then this function will return
false for these elements as well. To properly traverse an array
which may contain empty elements see the <function>each</function>
function.
</para>
</warning>
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<para>
<function>prev</function> behaves just like
<function>next</function>, except it rewinds the internal array
pointer one place instead of advancing it.
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<para>
See also:
<function>current</function>, <function>end</function>
<function>next</function> and <function>reset</function>
</refsect1>
</refentry>
<refentry id="function.range">
<refnamediv>
<refname>range</refname>
<refpurpose>Create an array containing a range of integers</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>array <function>range</function></funcdef>
<paramdef>int <parameter>low</parameter></paramdef>
<paramdef>int <parameter>high</parameter></paramdef>
</funcsynopsis>
<para>
<function>range</function> returns an array of integers from
<parameter>low</parameter> to <parameter>high</parameter>,
inclusive.
<para>
See <function>shuffle</function> for an example of its use.
</refsect1>
</refentry>
<refentry id="function.reset">
<refnamediv>
<refname>reset</refname>
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<refpurpose>
Set the internal pointer of an array to its first element
</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>mixed <function>reset</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
<function>reset</function> rewinds <parameter>array</parameter>'s
internal pointer to the first element.
<para>
<function>reset</function> returns the value of the first array
element.
<para>
See also:
<function>current</function>, <function>each</function>, <function>next</function>
<function>prev</function> and <function>reset</function>
</refsect1>
</refentry>
<refentry id="function.rsort">
<refnamediv>
<refname>rsort</refname>
<refpurpose>Sort an array in reverse order</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>rsort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
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This function sorts an array in reverse order (highest to lowest).
<example>
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<title><function>rsort</function> example</title>
<programlisting>
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$fruits = array("lemon","orange","banana","apple");
rsort($fruits);
for (reset($fruits); list($key,$value) = each($fruits); ) {
echo "fruits[$key] = ", $value, "\n";
}
</programlisting>
</example>
This example would display:
<computeroutput>
fruits[0] = orange
fruits[1] = lemon
fruits[2] = banana
fruits[3] = apple
</computeroutput>
The fruits have been sorted in reverse alphabetical order.
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<para>
See also <function>arsort</function>, <function>asort</function>,
<function>ksort</function>, <function>sort</function> and <function>usort</function>.
</refsect1>
</refentry>
<refentry id="function.shuffle">
<refnamediv>
<refname>shuffle</refname>
<refpurpose>Shuffle an array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>shuffle</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
This function shuffles (randomizes the order of the elements in)
an array.
<example>
<title><function>shuffle</function> example</title>
<programlisting>
$numbers = range(1,20);
srand(time());
shuffle($numbers);
while (list(,$number) = each($numbers)) {
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echo "$number ";
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}
</programlisting></example>
<para>
See also <function>arsort</function>, <function>asort</function>,
<function>ksort</function>, <function>rsort</function>,
<function>sort</function> and <function>usort</function>.
</refsect1>
</refentry>
<refentry id="function.sizeof">
<refnamediv>
<refname>sizeof</refname>
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<refpurpose>Get the number of elements in an array</refpurpose>
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</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>int <function>sizeof</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
Returns the number of elements in the array.
<para>
See also:
<function>count</function>
</refsect1>
</refentry>
<refentry id="function.sort">
<refnamediv>
<refname>sort</refname>
<refpurpose>Sort an array</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>sort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
</funcsynopsis>
<para>
This function sorts an array. Elements will be arranged from lowest to
highest when this function has completed.
<example>
<title><function>sort</function> example</title>
<programlisting>
$fruits = array("lemon","orange","banana","apple");
sort($fruits);
for(reset($fruits); $key = key($fruits); next($fruits)) {
echo "fruits[$key] = ".$fruits[$key]."\n";
}
</programlisting></example>
This example would display:
<computeroutput>
fruits[0] = apple
fruits[1] = banana
fruits[2] = lemon
fruits[3] = orange
</computeroutput>
The fruits have been sorted in alphabetical order.
<para>
See also <function>arsort</function>, <function>asort</function>,
<function>ksort</function>, <function>rsort</function>, and <function>usort</function>.
</refsect1>
</refentry>
<refentry id="function.uasort">
<refnamediv>
<refname>uasort</refname>
<refpurpose>Sort an array with a user-defined comparison function and maintain index association</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>uasort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>function <parameter>cmp_function</parameter></paramdef>
</funcsynopsis>
<para>
This function sorts an array such that array indices maintain their
correlation with the array elements they are associated with. This is
used mainly when sorting associative arrays where the actual element
order is significant. The comparison function is user-defined.
</refsect1>
</refentry>
<refentry id="function.uksort">
<refnamediv>
<refname>uksort</refname>
<refpurpose>Sort an array by keys using a user-defined comparison function</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>uksort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>function <parameter>cmp_function</parameter></paramdef>
</funcsynopsis>
<para>
This function will sort the keys of an array using a
user-supplied comparison function. If the array you wish to sort
needs to be sorted by some non-trivial criteria, you should use
this function.
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<example>
<title><function>uksort</function> example</title>
<programlisting>
function mycompare($a, $b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(4 => "four", 3 => "three", 20 => "twenty", 10 => "ten");
uksort($a, mycompare);
while(list($key, $value) = each($a)) {
echo "$key: $value\n";
}
</programlisting></example>
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This example would display:
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<computeroutput>
20: twenty
10: ten
4: four
3: three
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</computeroutput>
1999-06-06 18:51:02 +00:00
<para>
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See also <function>arsort</function>, <function>asort</function>,
<function>uasort</function>, <function>ksort</function>,
<function>rsort</function> and <function>sort</function>.
1999-06-06 18:51:02 +00:00
</refsect1>
</refentry>
<refentry id="function.usort">
<refnamediv>
<refname>usort</refname>
<refpurpose>Sort an array by values using a user-defined comparison function</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<funcsynopsis>
<funcdef>void <function>usort</function></funcdef>
<paramdef>array <parameter>array</parameter></paramdef>
<paramdef>function <parameter>cmp_function</parameter></paramdef>
</funcsynopsis>
<para>
This function will sort an array by its values using a
user-supplied comparison function. If the array you wish to sort
needs to be sorted by some non-trivial criteria, you should use
this function.
<para>
The comparison function must return an integer less than, equal to, or
greater than zero if the first argument is considered to be respectively
less than, equal to, or greater than the second. If two members compare
as equal, their order in the sorted array is undefined.
<example>
<title><function>usort</function> example</title>
<programlisting>
function cmp($a,$b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$a = array(3,2,5,6,1);
usort($a, cmp);
while(list($key,$value) = each($a)) {
echo "$key: $value\n";
}
</programlisting></example>
This example would display:
<computeroutput>
0: 6
1: 5
2: 3
3: 2
4: 1
</computeroutput>
1999-06-28 02:07:12 +00:00
<note>
<para>
Obviously in this trivial case the <function>rsort</function> function
would be more appropriate.
</para>
</note>
<warning>
<para>
The underlying quicksort function in some C libraries (such as on
Solaris systems) may cause PHP to crash if the comparison function
does not return consistent values.
</para>
</warning>
1999-06-06 18:51:02 +00:00
<para>
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See also:
<function>arsort</function>, <function>asort</function>,
<function>ksort</function>, <function>rsort</function> and
<function>sort</function>.
1999-06-06 18:51:02 +00:00
</refsect1>
</refentry>
</reference>
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