如何在 PHP 中將字串轉換為數字

  1. 使用顯式型別轉換在 PHP 中將字串轉換為數字
  2. 使用 intval() 函式在 PHP 中將字串轉換為數字
  3. 使用 settype() 函式在 PHP 中將字串轉換為數字

在本文中,我們將介紹在 PHP 中將字串轉換為數字的方法。

  • 使用顯式型別轉換
  • 使用 intval()/floatval() 函式
  • 使用 settype() 函式

使用顯式型別轉換在 PHP 中將字串轉換為數字

顯式型別轉換將任何型別的變數轉換為所需型別的變數。它將變數轉換為原始資料型別。將變數顯式型別轉換為 intfloat 的正確語法如下

$variableName = (int)$stringName
$variableName = (float)$stringName

變數 variableName 是整數變數,用於儲存 number 的值。變數 stringName 是數字字串。我們還可以將非數字字串轉換為數字。

<?php  
$variable = "10";
$integer = (int)$variable;
echo "The variable $variable has converted to a number and its value is $integer.";  
echo "\n";

$variable = "8.1";
$float = (float)$variable;
echo "The variable $variable has converted to a number and its value is $float.";  
?>

輸出:

The variable 10 has converted to a number and its value is 10.
The variable 8.1 has converted to a number and its value is 8.1.

對於非數字字串,我們將得到 0 作為輸出。

<?php  
$variable = "abc";
$integer = (int)$variable;
echo "The variable has converted to a number and its value is $integer.";  
?>

輸出:

The variable has converted to a number and its value is 0.

使用 intval() 函式在 PHP 中將字串轉換為數字

intval() 函式將字串轉換為整型 int

floatval() 函式將字串轉換為浮點數 float

這些函式接受的引數是一個字串,返回值分別是一個整數或一個浮點數。

intval( $StringName );  

變數 StringName 是字串型別。

<?php  
$variable = "53";
$integer = intval($variable);
echo "The variable $variable has converted to a number and its value is $integer.";  
echo "\n";

$variable = "25.3";
$float = floatval($variable);
echo "The variable $variable has converted to a number and its value is $float.";  
?>

輸出:

The variable 53 has converted to a number and its value is 53.
The variable 25.3 has converted to a number and its value is 25.3.

如果給定的字串是數字和字串表示形式的混合,例如 2020Time,則 intval() 將返回 2020。但是,如果給定的字串不是以數字開頭,則它將返回 0floatval() 方法也是如此。

示例程式碼:

<?php  
$variable = "2020Time";
$integer = intval($variable);
echo "The variable $variable has converted to a number and its value is $integer.";  
echo "\n";

$variable = "Time2020";
$integer = intval($variable);
echo "The variable $variable has converted to a number and its value is $integer.";  
echo "\n";

$variable = "25.3Time";
$float = floatval($variable);
echo "The variable $variable has converted to a number and its value is $float.";  
echo "\n";

$variable = "Time25.3";
$float = floatval($variable);
echo "The variable $variable has converted to a number and its value is $float.";  
?>

輸出:

The variable 2020Time has converted to a number and its value is 2020.
The variable Time2020 has converted to a number and its value is 0.
The variable 25.3Time has converted to a number and its value is 25.3.
The variable Time25.3 has converted to a number and its value is 0.

使用 settype() 函式在 PHP 中將字串轉換為數字

settype() 函式將任何資料型別的變數轉換為特定資料型別。它接受兩個引數,變數和型別名稱。

settype($variableName, "typeName");

variableName 是我們要轉換為數字的任何資料型別的變數。typeName 是我們要為 variableName 變數使用的資料型別的名稱。

<?php  
$variable = "45";
settype($variable, "integer");
echo "The variable has converted to a number and its value is $variable.";  
?>

settype() 函式將 $variable 的型別從字串設定為整型 integer。它僅適用於原始資料型別。

輸出:

The variable has converted to a number and its value is 45.

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