php string to int

php string to int

Conversion method

In In PHP, we can use 3 ways to convert strings into integers.

1. Forced type conversion method

Forced type conversion method is the method of "adding the target type enclosed in parentheses before the variable to be converted".

<?php 
$foo = "1"; // $foo 是字符串类型 
$bar = (int)$foo; // $bar 是整型 
?>

For integers, the cast type name is int or integer.

2. Built-in function method

The built-in function method uses PHP's built-in function intval to convert variables.

<?php 
$foo = "1"; // $foo 是字符串类型 
$bar = intval($foo); // $bar 是整型 
?>

The format of the intval function is: int intval(mixed $var [, int $base]);

3. Format string method

Format string method is to use sprintf's %d to format the specified variable to achieve the purpose of type conversion.

<?php 
$foo = "1"; // $foo 是字符串类型 
$bar = sprintf("%d", $foo); // $bar 是字符串类型 
?>

Strictly speaking, the conversion result of sprintf is still string type, so it should not be regarded as a way to convert strings into integers. But the string value after his processing has indeed become "an integer that is forced to be converted to a string type."

Performance

int > intval > sprintf

From a readability perspective, the sprintf method code is relatively long, and the results are You may need to perform forced type conversion again, and the intval function is a typical process-oriented conversion. Forced type conversion more directly conveys the idea of ​​"I want to convert" to the reader.

In terms of efficiency, forced type conversion is also the fastest conversion method (the integer variable value can be obtained directly).

Related recommendations: "PHP Tutorial"

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