Backend DevelopmentPHP TutorialPHP introductory tutorial summary of array usage (create, delete, traverse, sort, etc.)PHP introductory tutorial summary of array usage (create, delete, traverse, sort, etc.)
The examples in this article summarize the usage of PHP arrays. Share it with everyone for your reference, the details are as follows:
Demo1.php
<?php //创建一个数组变量 $userNames = array('张三','李四','王五'); //将这个数组打印出来 // echo $userNames;//Array // $userName = '张三'; // echo $userName;//张三 //如果你想打印出这个数组的某一个元素 //那你必须找到这个元素的下标，键(key) //0，1，2 //echo $userNames[2];//王五 //print_r -- 打印关于变量的易于理解的信息。 //print_r($userNames);//Array ( [0] => 张三 [1] => 李四 [2] => 王五 ) //$userNames 是一个数组变量，而 $userNames[x] 可以理解成数组变量下的小变量 $userNames[4] = '赵七'; print_r($userNames);//Array ( [0] => 张三 [1] => 李四 [2] => 王五 [4] => 赵七 ) ?>
Demo2.php
<?php //range -- 建立一个包含指定范围单元的数组 //range 包含指定数组 //包含两种东西，一种叫做键(key)，一种叫做值(value) //key 是自动生成的，默认从 0 开始，每次 +1 //value 是你自己赋值的 //$numbers = range(1,4); //print_r($numbers); //Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 ) // $letters = range('a','e'); // print_r($letters);//Array ( [0] => a [1] => b [2] => c [3] => d [4] => e ) // echo $letters[3]; ?>
Demo3.php
<?php
$userNames = array('张三','李四','王五');
//通过循环来显示数组里的所有值
//从 0-5 之间循环
// for($i=0;$i<3;$i++){
// echo ($i+1).'-->'.$userNames[$i].'<br/>';
// }
/*
* 1-->张三
* 2-->李四
* 3-->王五
* */
// echo count($userNames); //3
// for($i=0;$i<count($userNames);$i++){
// echo ($i+1).'-->'.$userNames[$i].'<br/>';
// }
//如果 key 不是从 0 开始，或者说，压根不是数字，那么就无法用无精打采循环来实现显示数据列表
//通过 foreach 循环来遍历数组，这方式好处，不需要去考虑 key
// foreach ($userNames as $value){
// echo $value.'<br/>';
// }
//foreach 遍历 $key => $value
// foreach ($userNames as $keyaaa => $value){
// echo $keyaaa.'-->'.$value.'<br/>';
// }
/**
* 0-->张三
* 1-->李四
* 2-->王五
* */
//所以，你要先做个判断
if(is_array($userNames)){
foreach ($userNames as $key => $value){
echo $key.'-->'.$value.'<br/>';
}
}else{
echo $userNames;
}
?>
Demo4.php
<?php $userNames = array('张三','李四','王五'); print_r($userNames); echo $userNames[0]; ?>
Demo5.php
<?php //创建自定义键(key)的数组 //如果你不去声明元素的 key ,那么从开始 0 计算 // $userNames = array('baidu'=>'张三','李四','王五'); // print_r($userNames); //Array ( [baidu] => 张三 [0] => 李四 [1] => 王五 ) $userNames = array('baidu'=>'张三','taobao'=>'李四','360'=>'王五'); print_r($userNames); //Array ( [baidu] => 张三 [taobao] => 李四 [360] => 王五 ) echo $userNames['baidu']; ?>
Demo6.php
<?php //先创建只一个元素的数组 $userAge = array('chaoyv'=>25); //打印出 chaoyv 的年龄 //echo $userAge['chaoyv']; //25 //将以前的数组，追加两条，这里说的下标，键，key 是一个东西 $userAge['yike'] = 30; $userAge['wife'] = 24; print_r($userAge); ?>
Demo7.php
<?php
//array 关键字都可以不要，就能创建数组
$userAges['chaoyv'] = 25;
//print_r($userAges); //Array ( [chaoyv] => 25 )
$userAges['yike'] = 30;
$userAges['wife'] = 24;
//print_r($userAges); //Array ( [chaoyv] => 25 [yike] => 30 [wife] => 24 )
//这里无法使用 for 循环将数据全部显示出来，只能通过 foreach 遍历出来
foreach ($userAges as $value){
echo $value.'<br/>';
}
?>
Demo8.php
<?php // $userAges['chaoyv'] = 25; // $userAges['yike'] = 30; // $userAges['wife'] = 24; $username = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之'); //print_r($username); //each 的使用 //each -- 返回数组中当前的键／值对并将数组指针向前移动一步 //这里有一个指针，默认情况下，指针是指定第一个键值对 //这里的第一个键值对是 '世'=>'何开' //如果each($username),那么获取的就是第一个键值对 '世'=>'何开' //each 这个函数返回的是一个数组， //each 将第一个键值对获取到，然后包装成一个新的数组。 //print_r(each($username)); //相当于 $a = Array ( [1] => 何开 [value] => 何开 [0] => 世 [key] => 世 ) //$a = each($username); //echo $a[value]; print_r(each($username)); echo '<br/>'; print_r(each($username)); ?>
Demo9.php
<?php
$username = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之');
//这里，我们怎么使用 each 来循环所有的数据呢？
//相当于 $a = Array ( [1] => 何开 [value] => 何开 [0] => 世 [key] => 世 )
//两个感叹号，表示真是存在的数据转换成布尔值
// echo !!each($username);//说明有数据，有数据，用布尔值的理念就是真(true)
// echo !!each($username);
// echo !!each($username);
// echo !!each($username);//第四个是假的
while (!!$a = each($username)){
echo $a['key'].'-->'.$a['value'].'<br/>';
}
// $a = each($username);
// echo $a[0].'---'.$a[1].'<br/>';
// $a = each($username);
// echo $a[0].'---'.$a[1].'<br/>';
// $a = each($username);
// echo $a[0].'---'.$a[1].'<br/>';
// /**
// * 世---何开
// * 血---赵血儿
// * 学---墨学之
// * */
?>
Demo10.php
<?php // $usernames = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之'); // $a = each($usernames); // //世-->何开 // echo $a['key']; // echo '-->'; // echo $a['value']; // $a = each($usernames); // //血-->赵血儿 // echo $a['key']; // echo '-->'; // echo $a['value']; // //list -- 把数组中的值赋给一些变量 // $a = array('aaa','bbb','ccc','ddd'); //// print_r($a);//Array ( [0] => aaa [1] => bbb [2] => ccc [3] => ddd ) // list($var1,$var2,$var3,$var4) = $a; // echo $var4; // $usernames = array(0=>'何开','血'=>'赵血儿','学'=>'墨学之'); // //list 只能认识 key 为数字的 // //自定义的字符串 key 是无法使用 list 来识别的 // list($a,$b,$c) = $usernames; // echo $a;//何开 $usernames = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之'); //相当于 $a = Array ( [1] => 何开 [value] => 何开 [0] => 世 [key] => 世 ) list($name,$username) = each($usernames); echo $username; ?>
Demo11.php
<?php $usernames = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之'); $a =each($usernames); echo $a[key]; $a =each($usernames); echo $a[key]; //第三次，我想取数组的第一条数组 //只要将数组的指针调整到第一个位置即可 //reset -- 将数组的内部指针指向第一个单元 reset($usernames); $a = each($usernames); echo $a[key]; //世血世 ?>
Demo12.php
<?php // $usernames = array('世'=>'何开','境'=>'何开','血'=>'赵血儿','学'=>'墨学之'); // print_r($usernames); // echo '<br/>'; // //array_unique -- 移除数组中重复的值 // //创建了一个新数组，而新数组呢，已经移除掉了，旧的数组原封不动 // $a = array_unique($usernames); // print_r($a); $numbers = array(1,24,2,1,3,4,2,6,4,2,4,56,2,4,5); print_r($numbers); $newNumbers = array_unique($numbers); print_r($newNumbers); ?>
Demo13.php
<?php $usernames = array('世'=>'何开','境'=>'何开','血'=>'赵血儿','学'=>'墨学之'); print_r($usernames); echo '<br/>'; //array_flip -- 交换数组中的键和值 $newUsernames = array_flip($usernames); print_r($newUsernames); /** * Array ( [世] => 何开 [境] => 何开 [血] => 赵血儿 [学] => 墨学之 ) * Array ( [何开] => 境 [赵血儿] => 血 [墨学之] => 学 ) * */ ?>
Demo14.php
<?php
//创建一个单一的数组
$products = array(
array('苹果','6','28.8'),
array('猪肉','2','18.8'),
array('饼干','4','48.8')
);
//print_r($products);
//将 $products 第一条元素取出来
//print_r($products[2]);
//数组里的数组
echo "|".$products[0][0]."|".$products[0][1]."|".$products[0][2]."|<br />";
echo "|".$products[1][0]."|".$products[1][1]."|".$products[1][2]."|<br />";
echo "|".$products[2][0]."|".$products[2][1]."|".$products[2][2]."|<br />";
?>
Demo15.php
<?php
//创建一个单一的数组
$products = array(
array('苹果','6','28.8'),
array('猪肉','2','18.8'),
array('饼干','4','48.8')
);
//首先要求出外面数组的长度
//echo count($products);
for($i=0; $i<count($products);$i++){
for($j=0;$j<count($products[$i]);$j++){
echo '|'.$products[$i][$j];
}
echo "|<br/>";
}
/*
* |苹果|6|28.8|
* |猪肉|2|18.8|
* |饼干|4|48.8|
* **/
?>
Demo16.php
<?php
//创建一个单一的数组
$products = array(
array('产品'=>'苹果','数量'=>'6','价格'=>'28.8'),
array('产品'=>'猪肉','数量'=>'3','价格'=>'25.8'),
array('产品'=>'饼干','数量'=>'2','价格'=>'26.8')
);
//print_r($products) ;
// for($i=0;$i<count($products);$i++){
// foreach ($products[$i] as $key => $value){
// echo $key.'--'.$value.'|';
// }
// echo '<br/>';
// }
for($i=0;$i<count($products);$i++){
while (!!list($key,$value)=each($products[$i])){
echo $key.'--'.$value.'|';
}
echo '<br/>';
}
/**
* 产品--苹果|数量--6|价格--28.8|
* 产品--猪肉|数量--3|价格--25.8|
* 产品--饼干|数量--2|价格--26.8|
* */
?>
Demo17.php
<?php // //sort -- 对数组排序 // $fruit = array('banner','orange','apple'); // //没有排序前，一般是按照 key 的顺序进行显示 // //print_r($fruit); // //排序之后 // sort($fruit); // print_r($fruit); $numbers = array(45,44,27,574,241,7,45,1,5,2,4,5); print_r($numbers); rsort($numbers); echo '<br/>'; print_r($numbers); //按照数字的话，要看整体的数字的大小，按照字符串的话，只看第一位大小 // $numbers = array(2,12,3); // sort($numbers,SORT_NUMERIC); // print_r($numbers);Array ( [0] => 2 [1] => 3 [2] => 12 ) // $numbers = array(2,12,3); // sort($numbers,SORT_STRING); // print_r($numbers);//Array ( [0] => 12 [1] => 2 [2] => 3 ) ?>
Demo18.php
<?php //asort -- 对数组进行排序并保持索引关系 $fruit = array('banner','orange','apple'); // sort($fruit); // print_r($fruit); //Array ( [0] => apple [1] => banner [2] => orange ) asort($fruit); print_r($fruit); //Array ( [2] => apple [0] => banner [1] => orange ) ?>
Demo19.php
<?php $fruit = array('b'=>'banner','o'=>'orange','a'=>'apple'); //ksort -- 对数组按照键名排序 ksort($fruit) ; print_r($fruit); //Array ( [a] => apple [b] => banner [o] => orange ) ?>
Demo20.php
<?php
//echo '<img src="/static/imghwm/default1.png" data-src="images/mm1.jpg" class="lazy" / alt="PHP introductory tutorial summary of array usage (create, delete, traverse, sort, etc.)" >';
//创建一个数组
$pic = array('mm1.jpg','mm2.jpg','mm3.jpg','mm4.jpg','mm5.jpg');
//数组进行随机打乱
//shuffle($pic);
//多数组进行反向排序,array 打头的函数，一般会创建一个新数组
$a = array_reverse($pic);
for($i=0;$i<3;$i++){
echo '<img src="/static/imghwm/default1.png" data-src="images/'.$a[$i].'" class="lazy" style="max-width:90%" / alt="PHP introductory tutorial summary of array usage (create, delete, traverse, sort, etc.)" >';
echo "\n";
}
?>
Demo21.php
<?php $userName = array('张三'); print_r($userName); //这个函数的返回值将得到 ，目前数组的元素个数 //array_unshift -- 在数组开头插入一个或多个单元 //在开头插入数据 array_unshift($userName,'李四') ; //在结尾插入数据 array_push($userName,'吴者然'); //删除开头的元素 array_shift($userName); //删除结尾的元素 array_pop($userName); print_r($userName); ?>
Demo22.php
<?php $fruit = array('banner','orange','apple'); //这个函数用来获取一个数组中的键(key) //第二个参数表明随即获取几个 // $a = array_rand($fruit,1); // echo $fruit[$a]; $a = array_rand($fruit,2); echo $fruit[$a[0]].' '.$fruit[$a[1]]; ?>
Demo23.php
<?php $username = array('世'=>'何开','血'=>'赵血儿','学'=>'墨学之'); //默认情况下，指针在第一条数据 //获取指针的当前元素，current 并没有将指针移到下一步 // echo current($username); // echo current($username); // echo current($username); // echo next($username); // echo current($username); // echo next($username); // echo current($username); // //reset -- 将数组的内部指针指向第一个单元 // echo reset($username); // echo sizeof($username);//count $numbers = array(1,4,5,656,7,5,7,4,7,4,5,7); //array_count_values -- 统计数组中所有的值出现的次数 print_r(array_count_values($numbers)); ?>
Demo24.php
<?php $a=$b=$c=''; $fruits = array('a'=>'apple','b'=>'banner','c'=>'orange'); //通过标量函数将字符串键(key)设置成变量，然后将值赋给了这个变量 extract($fruits); echo $a; echo $c; echo $b; //appleorangebanner ?>
I hope this article will be helpful to everyone in PHP programming.
For more PHP introductory tutorials on array usage summary (creation, deletion, traversal, sorting, etc.), please pay attention to the PHP Chinese website!
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