php常见数组函数

（1）array_rand(array,number) //number指定返回随机( 键名 )的多少

<?php
$a=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
print_r(array_rand($a,1));
?>

返回数为1，将返回一个随机键名

<?php
$a=array("a"=>"red","b"=>"green","c"=>"blue","d"=>"yellow");
print_r(array_rand($a,2));    //Array ( [0] => a [1] => d ) 
?>

返回数多个，将返回随机带键名的数组,经常与array_flip()配合使用

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（2）range(from,to,length);

print_r(range(0,20,2));
第三个参数是数组元素之间的步长

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（3）数组遍历

foreach有两种遍历方式，带键名与不带键名，只能遍历数组与对象

$list = array('weidapao',"jack","ugly",'breast','army','joe');

for($i = 0;$i < count($list);$i++){
    echo $list[$i]."<br>";
};

foreach ($list as $key => $value) {
    echo $value."<br>";
}
echo "<br>";

$hotStone = [
    '战士' => '奥金斧',
    '猎人'=>'恐龙学',
    '法师'=>'法力浮龙',
    '牧师'=>'龙息药水',
    '萨满'=>'蛮鱼图腾'
];
foreach($hotStone as $key=>$val){
    echo '职业是:'.$key.'-特点是:'.$val.'<br>';
};

while($a = each($list)){
    echo $a['key']."-".$a['value'].'<br>';
}

（4）list解构赋值

$hero = array("weien","blind","crocodile");

list($adc,$jungle,$top) = $hero;

echo "abc 是 $adc | jungle 是 $jungle | top 是 $top";

（5）不改变原数组的一些数组方法

$multi = array(5,8,9,7,6,6,5,5);
$unique = array_unique($multi);
print_r($unique); //不会改变原数组

array_flip(array); 交换数组的键名与键值

$relative = array('name'=>'weiwei','age'=>22,'salary'=>2200);
$turnover = array_flip($relative);
print_r($turnover);   //交换数组的键名与键值

（6）排序函数

ksort() 函数对关联数组按照键名进行升序排序
请使用asort() 函数对关联数组按照键值进行升序排序

（7）数组插入方式

$table = array();

$table[] = 'watar';
$table[] = 'rice';
$table[] = 'salt';
print_r($table);  //Array ( [0] => watar [1] => rice [2] => salt ) 

（8）遍历二维数组

$user = [
    ["id"=>1,"name"=>'fighter',"salary"=>'5000'],
    ["id"=>2,"name"=>'hank',"salary"=>'6000'],
    ["id"=>3,"name"=>'brumu',"salary"=>'4000'],
    ["id"=>4,"name"=>'coco',"salary"=>'3000'],
    ["id"=>5,"name"=>'gorge',"salary"=>'2000'],
    ["id"=>6,"name"=>'lesbin',"salary"=>'1000']
];
foreach($user as $val){
    echo '编号是:'.$val['id'];
    echo '名字是:'.$val['name'];
    echo '工资是:'.$val['salary'];
    echo "<br>";
};

（9）去掉字符串指定分隔，并将分隔后第一个字母转大写

$test = "wei_da_pao";

function transfer($str){
    $return = '';
    $str = explode('_',$str);

    foreach ($str as $value) {
        $return .= ucfirst($value);
    };
    return $return;
}
//Notice: Undefined variable: return in D:\phpDemo\all\php_Basic\str_func.php on line 
var_dump(transfer($test));

使用拼接字符串变量前需要先声明为字符串，不然会产生Notice警告

echo lcfirst('bady');
echo "<br>";
echo ucwords('we are the best man, you are good enough');
echo "<br>";
echo strtolower('YAKEXI');
echo "<br>";
echo strtoupper('leikesa');

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• lcfirst() 把字符串中的首字符转换为小写
• ucwords() 把字符串中每个单词的首字符转换为大写
• strtoupper() 把字符串转换为大写
• strtolower() 把字符串转换为小写