How to distinguish between intval() and (int) in PHP

This article mainly compares the functions and definitions of intval() type conversion and (int) forced type conversion with some examples to distinguish between the two.

1.intval() function

Syntax:

intval ( mixed $value , int $base = 10 ) : int

• value is the quantity value to be converted into integer

• base is the base used for conversion (not Default is decimal)

• Return value: int type variable

PS: Unless value is a string, otherwise base will not work.

Example:

<?php
echo intval(42)."<br>";                      // 42
echo intval(4.2)."<br>";                     // 4
echo intval(&#39;42&#39;)."<br>";                    // 42
echo intval(&#39;+42&#39;)."<br>";                   // 42
echo intval(&#39;-42&#39;)."<br>";                   // -42
echo intval(042)."<br>";                     // 34
echo intval(&#39;042&#39;)."<br>";                   // 42
echo intval(1e10)."<br>";                    // 1410065408
echo intval(&#39;1e10&#39;)."<br>";                  // 1
echo intval(0x1A)."<br>";                    // 26
echo intval(42000000)."<br>";                // 42000000
echo intval(420000000000000000000)."<br>";   // 0
echo intval(&#39;420000000000000000000&#39;)."<br>"; // 2147483647
echo intval(42, 8)."<br>";                   // 42
echo intval(&#39;42&#39;, 8)."<br>";                 // 34
echo intval(array())."<br>";                 // 0
echo intval(array(&#39;foo&#39;, &#39;bar&#39;))."<br>";     // 1
echo intval(false)."<br>";                   // 0
echo intval(true)."<br>";                    // 1
?>

2. (int) forced conversion

Demonstration ：

<?php
echo (int)42;     // 42
echo "<br>";
echo (int)4.2;    // 4
echo "<br>";                   
echo (int)&#39;42&#39;;   // 42
echo "<br>";                    
echo (int)&#39;+42&#39;;  // 42
echo "<br>";                  
echo (int)&#39;-42&#39;;  // -42
echo "<br>";                 
echo (int)042;    //  34
echo "<br>";                    
echo (int)&#39;042&#39;;  // 42
echo "<br>";                  
echo (int)1e10;   // 1410065408
echo "<br>";                    
echo (int)&#39;1e10&#39;; //2147483647
echo "<br>";                
echo (int)0x1A;   // 26
echo "<br>";                    
echo (int)42000000;// 42000000
echo "<br>";                
echo (int)420000000000000000000;  //-1609564160
echo "<br>"; 
echo (int)&#39;420000000000000000000&#39;; //2147483647
echo "<br>";

/*echo intval(42, 8)."<br>";                   
echo intval(&#39;42&#39;, 8)."<br>";              */
/*int的强制转换不是函数，所以无法实现*/  
                
echo (int)array();// 0
echo "<br>";                 
echo (int)array(&#39;foo&#39;, &#39;bar&#39;);//1
echo "<br>";     
echo (int)false;   //0
echo "<br>";              
echo (int)true;    //1
echo "<br>";                   
?>

3. Summary:

1. ##int forced conversion and The intval() function remains consistent when facing boolean, int, float, array (not exceeding each the maximum value displayed for each type).

2. intval()If the parameter is a string, returns the integer value represented by the digit string before the first character in the string that is not a digit. If the first character in the string is ‘-’, counting starts from the second character. If the parameter is a dotted number, its rounded value is returned.

3. The maximum value of the int type is 2147483647Generally during type conversion, if the maximum value is exceeded, the maximum value is displayed, ( int) will display -1609564160.

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