配列の使用法


「5.10配列の使用法」からのメモ。

  • 和集合
<?php
function union($a , $b)
{
  $union = array_merge($a , $b);
  return array_unique($union);
}

$foo = array("a" , "b" , "c");
$bar = array("aa" , "cc" , "b");

$hoge = union($foo , $bar);
print_r($hoge);
?>
Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => aa
    [4] => cc
)
  • 積集合
<?php
$foo = array("a" , "b" , "c");
$bar = array("aa" , "cc" , "b");

$hoge = array_intersect($foo , $bar);
print_r($hoge);
?>
Array
(
    [1] => b
)
  • 差集合?
<?php
$foo = array("a" , "b" , "c");
$bar = array("aa" , "cc" , "b");

$hoge = array_diff($foo , $bar);
print_r($hoge);
?>
Array
(
    [0] => a
    [2] => c
)
  • スタック
<?php
$hoge = array(10 , 20 , 30);
$v = array_pop($hoge);
echo "v = $v\n";

array_push($hoge , 100);
print_r($hoge);
?>
v = 30
Array
(
    [0] => 10
    [1] => 20
    [2] => 100
)
  • キュー
<?php
$hoge = array(10 , 20 , 30);
$v = array_shift($hoge);

echo "v = $v\n";

array_unshift($hoge , 100);
print_r($hoge);
?>
v = 10
Array
(
    [0] => 100
    [1] => 20
    [2] => 30
)