PHP专题-PHP数组(续)

16.取得关联数组的键名

$province=array("LiaoNing"=>"shenyang","HeiLongJiang"=>"Haerbin","JiLin"=>"Changchun");
while ($key=key($province)){
    echo $key."<br>";
    next($province);//使用next函数数组索引指针下移一位
}
?>

17.访问数组的键名和元素

<?php
$countries_languages
=array('China'=>'汉语','France'=>'法语','USA'=>'美国英语');
printf("<p>语言:%s.</p>\n",
      implode(',',array_values($countries_languages)));
printf("<p>国家:%s.</p>\n",
      implode(',',array_keys($countries_languages)));
?>

18.判断数组的类型

<?php
function isAssocArray($array){
    //是否为数组
    if(!is_array($array)){
        return false;
    }
    //处理键名
    $keys=array_keys($array);
    $tries=count($keys);
    if ($tries>4){
        $tries=4;
    }
for ($i=0;$i<$tries;$i++){
    //根据键名是否是数字
    if (!is_int($keys[$i])){
        return true;
    }
}
   return false;
}
//索引数组
$array_one=array(
    'http://www.google.cn',
    'http://www.baidu.com'
);
//关联数组
$array_two=array(
    'Google'=>'http://www.google.cn',
    'Baidu'=>'http://www.baidu.com'
);
if (isAssocArray($array_one)){
    echo "\$array_one是关联数组<br>";
}else {
    echo "\$array_one不是关联数组<br>";
}
if (isAssocArray($array_two)){
    echo "\$array_two是关联数组<br>";
}
?>

19.显示数组内容与结构

<?php
$customers=array(
        array('account'=>'raymond','name'=>'杜江',
        'age'=>28,'state'=>'中华人民共和国'),
        array('account'=>'lilia','name'=>'琳琳',
        'age'=>23,'state'=>'中华人民共和国'),
        array('account'=>'guojing','name'=>'郭靖',
        'age'=>36,'state'=>'宋朝'),
    );
 printf("print_r()函数:<pre>",print_r($customers,TRUE));
 printf("var_export()函数:<pre>%s</pre>",var_export($customers,TRUE));
 print 'var_dump()函数:<pre>';
 var_dump($customers);
 print '</pre>';
?>

20.移除数组中的指定元素

<?php
$dogs=array('Lassie'=>'Collie','Bud'=>'Sheepdog',
            'Rin-Tin-Tin'=>'German Shepherd','Snoopy'=>'Beagle');
printf("<pre>%s</pre>\n",var_export($dogs,TRUE));
//移除R-Tin-Tin这个数组元素
unset($dogs['Rin-Tin-Tin']);
printf("<pre>%s</pre>\n",var_export($dogs,TRUE));
?>

21.在数组顶部插入元素

<?php
$prices=array(5.95,10.75,11.25);
echo "原数组内容:<br><pre>";
print_r($prices);
echo "<br>";
//在该数组的顶部增加一个值
array_unshift($prices, 10.85);
echo "</pre>使用array_unshift增加了10.85的值:<br></pre>";
print_r($prices);
echo "<br>";
array_unshift($prices, 3.35,17.95);
echo "</pre>使用array_unshift又增加了3.35，17.95两个值:<br><pre>";
print_r($prices);
?>

22.在数组任意位置插入元素

<?php
function array_insert(&$array,$offset,$new){
    array_splice($array, $offset,0,$new);
}
$unscl=array('中国','法国','美国','英国');
printf("<pre>%s</pre>\n",var_export($unscl,TRUE));
array_insert($unscl, 2, '俄罗斯');
printf("<pre>%s</pre>\n",var_export($unscl,TRUE));
?>

23.数组元素的统计count()函数和sizeof()函数

<?php
$dogs=array('Lassie'=>'Collie','Bud'=>'Sheepdog','Rin-Tin-Tin'=>'Alsatian');
$brids=array('parrot','magpie','lorakeet','cuckoo');
echo count($dogs)."";
echo sizeof($brids);
?>

24.数组键名与值的对调array_flip()函数

<?php
$arry=array(
    'a'=>1,
    'b'=>2,
    'c'=>3
);
$flip_array=array_flip($arry);
print_r($arry);
?>

25.对数组元素分组统计array_values()函数

<?php
$countries=array('USA'=>'English','Spain'=>'Spanish',
            'China'=>'Chinese','UK'=>'English',
            'Mexico'=>'Spanish','Germany'=>'German',
            'Colombia'=>'Spanish','Canada'=>'English',
            'Russia'=>'Russian','Austria'=>'German',
            'France'=>'French','Argentina'=>'Spanish'
);
$languages=array_values($countries);
$language_count=array();
foreach ($languages as $language){
    if (!isset($language_count[$language])){
        $language_count[$language]=1;
    }else {
        $language_count[$language]++;
    }

}
?>
<table border="2" cellpadding="5" cellspacing="0" align="center">
<tr><th>语言</th><th>国家数</th></tr>
<?php
foreach ($language_count as $language => $number){
    echo "<tr><td>$language</td><td>$number</td></tr>\n";
}
?><?php
$countries=array('USA'=>'English','Spain'=>'Spanish',
            'China'=>'Chinese','UK'=>'English',
            'Mexico'=>'Spanish','Germany'=>'German',
            'Colombia'=>'Spanish','Canada'=>'English',
            'Russia'=>'Russian','Austria'=>'German',
            'France'=>'French','Argentina'=>'Spanish'
);
$languages=array_values($countries);
$language_count=array();
foreach ($languages as $language){
    if (!isset($language_count[$language])){
        $language_count[$language]=1;
    }else {
        $language_count[$language]++;
    }

}
?>
<table border="2" cellpadding="5" cellspacing="0" align="center">
<tr><th>语言</th><th>国家数</th></tr>
<?php
foreach ($language_count as $language => $number){
    echo "<tr><td>$language</td><td>$number</td></tr>\n";
}
?>

26.数组内容过滤

<?php
function array_display($array,$pre=FALSE){
    $tag =$pre ? 'pre' : 'p';
    printf("<%s>%s<%s>\n",$tag,var_export($array,TRUE),$tag);
}
$arr=array(2,'two',0,'NULL',NULL,'FALSE',FALSE,'empty','');
$copy=array_filter($arr);
$reindexed=array_values($copy);
print '<p>原始数组:</p>';
array_display($arr,TRUE);
print '<p>过滤后的数组:</p>';
array_display($copy,TRUE);
print '<p>过滤后和重新索引的数组</p>';
array_display($reindexed,TRUE);
?>