php intval int difference

In PHP, both intval and int functions can be used to convert strings into integer values. However, there is a subtle difference between the two. This article will introduce in detail the differences between these two functions and what you need to pay attention to when using them.

1. intval function

The intval function is a very commonly used function in PHP. Its function is to convert a string into integer data. The syntax is as follows:

int intval ( mixed $var , int $base = 10 )

Among them, the parameter var is a variable to be converted to an integer, and the parameter base is a base number, optional, and the default is 10.

The return value of the intval function is integer data.

2. int type

In PHP, the int type is an integer data type, representing an integer. You can cast to type int using (int). For example:

$var = 10.5;
$intVar = (int) $var;

In this example, the value of $intVar is 10 because casting 10.5 to an integer rounds down.

3. The difference between intval and int

Although both intval and int can convert strings into integer data, there are still obvious differences between them.

(1) Return value type

intval returns integer data, while (int) returns int type data.

(2) Processable data types

intval function can process various types of data, including strings, floating point numbers, etc. And (int) can only be used to convert numeric data to integer data.

(3) How to handle floating-point numbers

When the intval function converts floating-point numbers into integer numbers, it will be rounded down. And (int) will directly truncate the decimal part of the floating point number.

(4) Processing non-numeric type values

intval function will try to convert non-numeric type values ​​to integer, if the conversion cannot be performed, it will return 0. And (int) will be converted to 1 when encountering a non-numeric value.

4. Usage Precautions

When using intval for string conversion, please pay attention to the following:

(1) Base conversion

The second parameter of intval indicates the base number to be converted. The default is 10, that is, decimal is used. If you need to convert to other bases, such as binary, octal, hexadecimal, etc., you can do it by setting the second parameter. For example:

$val = "1101";
$binVal = intval($val,2); // 输出 13
$octVal = intval($val,8); // 输出 561
$hexVal = intval($val,16); // 输出 4353

(2) Handling special cases

When using intval for conversion, you need to pay attention to some special cases. For example:

$val1 = "3.14abc";
$val2 = "abc3.14";
$val3 = "abc";
$val4 = "null";
echo intval($val1); // 输出 3
echo intval($val2); // 输出 0
echo intval($val3); // 输出 0
echo intval($val4); // 输出 0

In this example, intval correctly converts the value of $val1 to 3, but for $val2, $val3, and $val4, intval all converts it to 0. Therefore, in practical applications, special attention needs to be paid to these situations.

Summary

In PHP, both intval and int can convert strings into integer data. However, there are still some differences between them. intval can handle various types of data, including floating point numbers, while (int) can only be used to convert numeric data to integer data. Moreover, when using intval for string conversion, you need to pay attention to special cases and base conversion. Therefore, in practical applications, it is necessary to select an appropriate conversion function according to specific needs.

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