How to convert string to integer in php

In PHP, converting string to integer is a very common operation. Usually, we need to convert the numbers in the string to integers in order to perform numerical calculations and other operations. The following will introduce the method of converting string to integer in PHP.

1. Use the (int) or intval() function

There are two methods in PHP to convert strings to integers. The first is to use the cast operator (int) to convert the string to an integer. As shown below:

$str = "123456"; $int = (int)$str; echo $int;

The output result is: 123456

Another method is to use the intval() function. This function can accept a parameter and convert it to an integer. As shown below:

$str = "123456"; $int = intval($str); echo $int;

The output result is: 123456

The advantage of using the (int) or intval() function is that it is very simple and easy to use, but it also has some limitations. First, this method will return 0 when the string contains non-numeric characters. Secondly, when the string contains decimals, this method converts to the integer part. Finally, if the value is too large to be represented as an integer, an error will be returned.

2. Use the strtol() function

PHP also provides a function called strtol(), which can convert a string into an integer and store the result in a pointer variable. As shown below:

$str = "123456"; $p = 0; $int = strtol($str, $p, 10); echo $int;

The output is: 123456

Here, the $p variable is a pointer to the first non-numeric character in the string. If the string contains no non-numeric characters, the pointer value is set to the length of the string. In addition, the strtol() function can also specify a base number. If not specified, the default base number 10 is used.

3. Use the sscanf() function

The sscanf() function in PHP can read data from a string and read it into the specified format. For example, we can use this function to convert a string to an integer. As shown below:

$str = "123456"; sscanf($str, "%d", $int); echo $int;

The output result is: 123456

Here, %d indicates that the input value is a decimal number.

Summary:

Converting string to integer is a very common operation in PHP. PHP provides several ways to accomplish this, such as using the (int) or intval() function, using the strtol() function and using the sscanf() function. No matter which method is used, it is very simple, efficient and reliable. Which method you choose depends mainly on your needs and preferences, but no matter which method you choose, you should make sure that the input string matches your expectations.

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