Detailed explanation of PHP array examples_php examples

As a C programmer, in the process of switching to PHP development, I had some confusion about PHP arrays. They are similar to C arrays, but also have some differences. Let’s comprehensively analyze PHP arrays and their Differences and connections with corresponding data types in C.

Classification of arrays:

1. Numeric array: also called index array, that is, numbers (starting from 0) are used as array subscripts. Equivalent to vector in C.

2. Associative array: Use string as array subscript. Equivalent to map in C.

3. Multidimensional array: Each element in the array is also an array. Each element in its subarray can also be an array.

Declaration of array:

1. Numeric array

a. In the following example, numeric ID keys will be automatically assigned.

$names = array("Peter","Joe","Lily");
b. In the following example, we manually assign numeric ID keys.

$names[0] = "Peter";
$names[1] = "Joe";
$names[2] = "Lily";

These ID keys can be used in scripts:

<&#63;php 
$names[0] = "Peter"; 
$names[1] = "Joe"; 
$names[2] = "Lily"; 
echo $names[0]." and ".$names[1]." are ".$names[2]."'s neighbors"; 
/* 何问起 hovertree.com */
&#63;> 

2. Associative array:

Example 1

$ages = array("Peter"=>32, "Joe"=>30, "Lily"=>28);

Example 2

This example is the same as Example 1, just another way to create an array.

$ages["Peter"] = "32"; 
$ages["Joe"] = "30"; 
$ages["Lily"] = "28"; 

Using associative arrays in scripts:

<?php 
$ages["Peter"] = "32"; 
$ages["Joe"] = "30"; 
$ages["Lily"] = "28"; 
echo "Peter is ".$ages["Peter"]." years old."; 
/* 何问起 hovertree.com */
?> 

The above script output:

Peter is 32 years old.

3. Multidimensional array:

In this example, we create a multidimensional array with automatically assigned numeric ID keys:

$families = array 
{ 
"Griffin"=>array 
{ 
"Peter", 
"Lois", 
"Megan" 
}, 
"Quagmire"=>array 
{ 
"Glenn" 
}, 
"Brown"=>array 
{ 
"Cleveland", 
"Loretta", 
"Junior" 
} 
}; 
echo "Is " . $families['Griffin'][2] . " a part of the Griffin family?"; 

The above code output:

Is Megan a part of the Griffin family?

1. for loop traversal

The for loop can only traverse the index array.

<&#63;php 
$names = array("Peter","Joe","Lily"); 
for($id=0;$id<count($names);++$id) 
{ 
echo $names[$id]; 
} 
&#63;> 

2. foreach traversal

You can traverse the index array or the associative array

Traverse the index array

foreach(array_expression as $value) 
{ 
循环体; 
} 
遍历关联数组 
foreach(array_expression as $key=>$value) 
{ 
循环体; 
} 

A. One-dimensional array traversal

Index array

<&#63;php 
$contact = array("李某","xx公司","abc@xx.com"); 
foreach($contact as $value) 
{ 
echo $value; 
} 
&#63;> 
<&#63;php 
$contact = array("姓名"=>"李某","公司"=>"xx公司","邮箱"=>"abc@xx.com"); 
foreach($contact as $key=>$value) 
{ 
echo $key.":".$value; 
} 
&#63;> 

B. Multi-dimensional array traversal

<&#63;php 
$wage = array( 
"市场部"=array( 
array(1,"李某","市场经理",8000), 
array(2,"王某","市场专员",5000), 
array(3,"刘某","市场专员",7000) 
), 
"产品部"=array( 
array(1,"李某","产品经理",9000), 
array(2,"王某","产品专员",6000), 
array(3,"刘某","产品专员",5000) 
), 
"账务部"=array( 
array(1,"李某","账务经理",7000), 
array(2,"王某","账务专员",6000), 
array(3,"刘某","账务专员",5000) 
) 
); 
foreach($wage as $section=>$table) 
{ 
echo $section."部门人员如下"; 
foreach($table as $row) 
{ 
foreach($row as $value) 
{ 
echo $value; 
} 
} 
} /* 何问起 hovertree.com */
&#63;> 

The above is a detailed explanation of the examples of php arrays introduced by the editor. I hope it will be helpful to everyone.