165 lines
4.6 KiB
Markdown
165 lines
4.6 KiB
Markdown
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---
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title: Php Arrays
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localeTitle: Php阵列
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---
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数组是一种数据结构，它将一个或多个相似类型的值存储在单个值中。例如，如果要存储100个数字，而不是定义100个变量，则很容易定义100个长度的数组。
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有三种不同类型的数组，每个数组值使用ID c访问，ID c称为数组索引。
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数值数组 - 具有数字索引的数组。以线性方式存储和访问值。
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关联数组 - 以字符串作为索引的数组。这将元素值与键值相关联而不是以严格的线性索引顺序存储。
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多维数组 - 使用多个索引访问包含一个或多个数组和值的数组
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注 - 内置数组函数在函数参考PHP数组函数中给出
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### 数字数组
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这些数组可以存储数字，字符串和任何对象，但它们的索引将由数字表示。默认情况下，数组索引从零开始。
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#### 例
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以下是显示如何创建和访问数字数组的示例。
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这里我们使用array（）函数来创建数组。该功能在功能参考中说明。
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```
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<html>
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<body>
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<?php
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/* First method to create array. */
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$numbers = array( 1, 2, 3, 4, 5);
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foreach( $numbers as $value ) {
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echo "Value is $value <br />";
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}
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/* Second method to create array. */
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$numbers[0] = "one";
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$numbers[1] = "two";
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$numbers[2] = "three";
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$numbers[3] = "four";
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$numbers[4] = "five";
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foreach( $numbers as $value ) {
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echo "Value is $value <br />";
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}
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?>
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</body>
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</html>
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```
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这将产生以下结果 -
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```
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Value is 1
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Value is 2
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Value is 3
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Value is 4
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Value is 5
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Value is one
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Value is two
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Value is three
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Value is four
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Value is five
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```
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### 关联数组
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关联数组在功能方面与数字数组非常相似，但它们的索引不同。关联数组将其索引作为字符串，以便您可以在键和值之间建立强关联。
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要将员工的工资存储在数组中，数字索引的数组将不是最佳选择。相反，我们可以使用员工姓名作为关联数组中的键，值将是他们各自的薪水。
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注意 - 打印时不要将关联数组保留在双引号内，否则不会返回任何值。
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```
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Example
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<html>
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<body>
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<?php
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/* First method to associate create array. */
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$salaries = array("mohammad" => 2000, "qadir" => 1000, "zara" => 500);
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echo "Salary of mohammad is ". $salaries['mohammad'] . "<br />";
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echo "Salary of qadir is ". $salaries['qadir']. "<br />";
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echo "Salary of zara is ". $salaries['zara']. "<br />";
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/* Second method to create array. */
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$salaries['mohammad'] = "high";
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$salaries['qadir'] = "medium";
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$salaries['zara'] = "low";
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echo "Salary of mohammad is ". $salaries['mohammad'] . "<br />";
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echo "Salary of qadir is ". $salaries['qadir']. "<br />";
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echo "Salary of zara is ". $salaries['zara']. "<br />";
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?>
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</body>
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</html>
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```
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这将产生以下结果 -
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```
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Salary of mohammad is 2000
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Salary of qadir is 1000
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Salary of zara is 500
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Salary of mohammad is high
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Salary of qadir is medium
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Salary of zara is low
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```
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### 多维数组
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多维数组主阵列中的每个元素也可以是一个数组。子数组中的每个元素都可以是数组，依此类推。使用多个索引访问多维数组中的值。
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例 在这个例子中，我们创建了一个二维数组，用于存储三个学科中三个学生的标记 -
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此示例是关联数组，您可以以相同的方式创建数字数组。
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```
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<html>
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<body>
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<?php
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$marks = array(
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"mohammad" => array (
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"physics" => 35,
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"maths" => 30,
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"chemistry" => 39
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),
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"qadir" => array (
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"physics" => 30,
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"maths" => 32,
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"chemistry" => 29
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),
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"zara" => array (
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"physics" => 31,
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"maths" => 22,
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"chemistry" => 39
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)
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);
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/* Accessing multi-dimensional array values */
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echo "Marks for mohammad in physics : " ;
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echo $marks['mohammad']['physics'] . "<br />";
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echo "Marks for qadir in maths : ";
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echo $marks['qadir']['maths'] . "<br />";
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echo "Marks for zara in chemistry : " ;
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echo $marks['zara']['chemistry'] . "<br />";
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?>
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</body>
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</html>
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```
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这将产生以下结果 -
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```
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Marks for mohammad in physics : 35
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Marks for qadir in maths : 32
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Marks for zara in chemistry : 39
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```
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