search
HomeBackend DevelopmentPHP Tutorial8个PHP数组面试题_php技巧

网上找的PHP数组题,准备自己做一遍并且记录下来。

1.写函数创建长度为10的数组,数组中的元素为递增的奇数,首项为1.

复制代码 代码如下:

    function arrsort($first,$length){

        $arr = array();
        for($i=$first;$i

            $arr[] = $i*2-1;
        }
        return $arr;
    }

    $arr1 = arrsort(1,10);
    print_r($arr1);

输出:

复制代码 代码如下:

Array ( [0] => 1 [1] => 3 [2] => 5 [3] => 7 [4] => 9 [5] => 11 [6] => 13 [7] => 15 [8] => 17 [9] => 19 )

2.创建长度为10的数组,数组中的数为递增的等比数,比值为3,首项为1.
复制代码 代码如下:

     //$num为比值
     function arrsort($first,$length,$num){

          $arr= array();
          for($i=$first;$i    
                //pow($num,$i-2);返回$num的($i-2)次方
                $arr[] = $num*pow($num,$i-2);
          }
          return $arr;
    }           

    $arr1 = arrsort(1,10,3);
    print_r($arr1);

输出:

复制代码 代码如下:

Array ( [0] => 1 [1] => 3 [2] => 9 [3] => 27 [4] => 81 [5] => 243 [6] => 729 [7] => 2187 [8] => 6561 [9] => 19683 )

3.求数组中最大数的下标.

复制代码 代码如下:

function maxkey($arr){

    $maxval = max($arr);
    foreach($arr as $key=>$val){
   
        if($maxval == $val){
       
            $maxkey = $key;
        }
    }
    return $maxkey;
}

$arr = array(0,-1,-2,5,"b"=>15,3);
echo maxkey($arr);

输出:

复制代码 代码如下:

b

4.创建一个长度为10的数组,数组中的元素满足斐波拉契数列的规律.

( 斐波那契数列,又称黄金分割数列,指的是这样一个数列:1、1、2、3、5、8、13、21、……在数学上,斐波纳契数列以如下被以递归的方法定义:F0=0,F1=1,Fn=F(n-1)+F(n-2)(n>=2,n∈N*). 特别指出:第0项是0,第1项是第一个1。)

复制代码 代码如下:

function arrFibo($len){

    $arr[0] = 0;
    $arr[1] = 1;
    for($i=2;$i    
        $arr[$i] = $arr[$i-1]+$arr[$i-2];
    }
    return $arr;
}

echo "

";<br>
print_r(arrFibo(10));<br>
echo "
";

输出:

复制代码 代码如下:

Array
(
    [0] => 0
    [1] => 1
    [2] => 1
    [3] => 2
    [4] => 3
    [5] => 5
    [6] => 8
    [7] => 13
    [8] => 21
    [9] => 34
)

5.计算数组中最大数和最小数的差.

两种方法:

①max/min

输出:

复制代码 代码如下:

102

②sort把元素按从小到大排序/rsort吧元素按从大到小排序

复制代码 代码如下:

function arrsub($arr){

    sort($arr);
    $min = $arr[0];

    rsort($arr);
    $max = $arr[0];

    $sub = $max - $min;

    return $sub;
}

$arr = array(-1,-2,100);

echo arrsub($arr);

输出:

102

6.写一个方法,将一个长度超过10的数组最后5项直接截取,不改变顺序变为前5项,如{1,2,3,4,5,6,7,8,9,10}变为{6,7,8,9,10,1,2,3,4,5}.

思路:先把数组截取相应的长度( array_slice ),再把2段数组拼接( array_merge )

复制代码 代码如下:

function arrsort($arr){

    $num = count($arr);

    if($num > 10){
   
        //array_slice($arr,起始位置,截取长度,保留索引(默认为false))
        $arr_firstpart = array_slice($arr,0,$num-5,true);
        $arr_lastpart = array_slice($arr,($num-5),5,true);
    }else{
   
        echo "数组不超过10个元素,请重新输入";
        exit();
    }
   
    //拼接
    $arr_new = array_merge($arr_lastpart,$arr_firstpart);

    return $arr_new;
}

$arr = array("a"=>1,2,3,8,9,6,"b"=>5,-1,"c"=>8,0,7);

echo "

";
<p>print_r($arr);</p>
<p>echo "<br>= = = = = 拼接后 = = = = <br><br>";</p>
<p>print_r(arrsort($arr));</p>
<p>echo "</p>
";

输出:

复制代码 代码如下:

Array
(
    [a] => 1
    [0] => 2
    [1] => 3
    [2] => 8
    [3] => 9
    [4] => 6
    [b] => 5
    [5] => -1
    [c] => 8
    [6] => 0
    [7] => 7
)

= = = = = 拼接后 = = = =
复制代码 代码如下:

Array
(
    [b] => 5
    [0] => -1
    [c] => 8
    [1] => 0
    [2] => 7
    [a] => 1
    [3] => 2
    [4] => 3
    [5] => 8
    [6] => 9
    [7] => 6
)

当数组不满足长度为10时:
复制代码 代码如下:

$arr = array("a"=>1,2,3);

输出:
复制代码 代码如下:

Array
(
    [a] => 1
    [0] => 2
    [1] => 3
)

= = = = = 拼接后 = = = =

数组不超过10个元素,请重新输入

7.将两个数组连接成一个新数组.

方法①使用array_merge()函数

复制代码 代码如下:

array_merge($arr1,$arr2);

方法②使用array_merge_recursive()函数递归追加数组

( array_merge_recursive() 函数与 array_merge() 函数 一样,将一个或多个数组的元素的合并起来,一个数组中的值附加在前一个数组的后面。并返回作为结果的数组。

但是,与 array_merge() 不同的是,当有重复的键名时,值不会被覆盖,而是将多个相同键名的值递归组成一个数组。)

复制代码 代码如下:

    $arr = array("a"=>1,"b"=>2,3);
    $arr2 = array("a"=>Dee,3,5);
   
    $arr3 = array_merge($arr,$arr2);
    $arr4 = array_merge_recursive($arr,$arr2);

    echo "

";<br>
    print_r($arr3);
<p>    echo "<br> = = = = = <br><br>";</p>
<p>    print_r($arr4);<br>
    echo "</p>
";

输出:

复制代码 代码如下:

Array
(
    [a] => Dee
    [b] => 2
    [0] => 3
    [1] => 3
    [2] => 5
)

 = = = = =
复制代码 代码如下:

Array
(
    [a] => Array
        (
            [0] => 1
            [1] => Dee
        )

    [b] => 2
    [0] => 3
    [1] => 3
    [2] => 5
)

第一个输出的数组中索引为"a"的值1被索引被第二个数组中索引为"a"的值Dee覆盖了。

方法③

复制代码 代码如下:

function arrsort($arr1,$arr2){

    $arr_new = $arr1;
   
    foreach($arr2 as $key=>$val){   
   
            $arr_new[] = $val;
    }

    return $arr_new;
}

$arr1 = array("a"=>1,"b"=>2,3);
$arr2 = array("a"=>Dee,"c"=>3,5);

echo "

";<br>
print_r(arrsort($arr1,$arr2));<br>
echo "
";

输出:

复制代码 代码如下:

Array
(
    [a] => 1
    [b] => 2
    [0] => 3
    [1] => Dee
    [2] => 3
    [3] => 5
)

如果是索引数组而且有重复的索引,则第二个数组中的这个重复的索引会被修改成新的索引。

8.数组逆序( 不能使用rsort函数,不能生成新数组 )

使用array_reverse()函数会创建新的数组,所以不能使用。

复制代码 代码如下:

$arr = array("a","b","c",1,10);
$i = "";//要替换位置的数的下标
$j = "";//临时变量
$k = "";//被替换位置的数的下标

$len = count($arr);
$half_len = floor($len/2);//向下取整,取整的值是循环的次数

for($i=0;$i

    $j = $arr[$i];
   
    //判断数组个数奇偶
    if($len%2!=0){ //奇数
   
        $k = $half_len*2-$i;
    }else{
       
        //偶数
        $k = $half_len*2-$i-1;
    }

    $arr[$i] = $arr[$k];
    $arr[$k] = $j;
}

echo "

";<br>
print_r($arr);<br>
echo "
";

输出:
复制代码 代码如下:

Array
(
    [0] => 10
    [1] => 1
    [2] => c
    [3] => b
    [4] => a
)
Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Explain the concept of session locking.Explain the concept of session locking.Apr 29, 2025 am 12:39 AM

Sessionlockingisatechniqueusedtoensureauser'ssessionremainsexclusivetooneuseratatime.Itiscrucialforpreventingdatacorruptionandsecuritybreachesinmulti-userapplications.Sessionlockingisimplementedusingserver-sidelockingmechanisms,suchasReentrantLockinJ

Are there any alternatives to PHP sessions?Are there any alternatives to PHP sessions?Apr 29, 2025 am 12:36 AM

Alternatives to PHP sessions include Cookies, Token-based Authentication, Database-based Sessions, and Redis/Memcached. 1.Cookies manage sessions by storing data on the client, which is simple but low in security. 2.Token-based Authentication uses tokens to verify users, which is highly secure but requires additional logic. 3.Database-basedSessions stores data in the database, which has good scalability but may affect performance. 4. Redis/Memcached uses distributed cache to improve performance and scalability, but requires additional matching

What is the full form of PHP?What is the full form of PHP?Apr 28, 2025 pm 04:58 PM

The article discusses PHP, detailing its full form, main uses in web development, comparison with Python and Java, and its ease of learning for beginners.

How does PHP handle form data?How does PHP handle form data?Apr 28, 2025 pm 04:57 PM

PHP handles form data using $\_POST and $\_GET superglobals, with security ensured through validation, sanitization, and secure database interactions.

What is the difference between PHP and ASP.NET?What is the difference between PHP and ASP.NET?Apr 28, 2025 pm 04:56 PM

The article compares PHP and ASP.NET, focusing on their suitability for large-scale web applications, performance differences, and security features. Both are viable for large projects, but PHP is open-source and platform-independent, while ASP.NET,

Is PHP a case-sensitive language?Is PHP a case-sensitive language?Apr 28, 2025 pm 04:55 PM

PHP's case sensitivity varies: functions are insensitive, while variables and classes are sensitive. Best practices include consistent naming and using case-insensitive functions for comparisons.

How do you redirect a page in PHP?How do you redirect a page in PHP?Apr 28, 2025 pm 04:54 PM

The article discusses various methods for page redirection in PHP, focusing on the header() function and addressing common issues like "headers already sent" errors.

Explain type hinting in PHPExplain type hinting in PHPApr 28, 2025 pm 04:52 PM

Article discusses type hinting in PHP, a feature for specifying expected data types in functions. Main issue is improving code quality and readability through type enforcement.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.