How to implement string conversion and number addition functions in PHP

PHP is a very powerful programming language that can handle a wide variety of data types. Among them, string and number processing are often used. However, sometimes you need to convert strings to numbers and add them, which requires some tricks and precautions. This article will introduce how to convert strings to numbers and add numbers in PHP.

1. Convert strings to numbers

In PHP, there are three functions that can convert strings into numbers, namely intval(), floatval() and doubleval(). The usage of these three functions is as follows:

1. intval()

intval() is a function in PHP that converts strings to integers. Its syntax is:

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

Among them, $var represents the string or value that needs to be converted, $base is optional and represents the incoming string The base, the default is decimal. For example:

$number1 = "123";
$number2 = "0x1a"; // Hexadecimal number
$number3 = "010"; // Octal number

var_dump(intval($number1)); // Output: int(123)
var_dump(intval($number2)); // Output: int(26)
var_dump(intval($number3) ); // Output: int(8)

As can be seen from the above example, intval() can convert a string into the corresponding numerical type. But it should be noted that when the string cannot be converted to a numeric type, intval() will return 0 instead of generating an error.

2. floatval()

floatval() is a function in PHP that converts strings to floating point numbers. Its syntax is:

float floatval (mixed $var)

Among them, $var represents the string or value that needs to be converted. For example:

$number1 = "123.45";
$number2 = "12.345e2"; // 12.345 x 10^2

var_dump(floatval($number1)); // Output: float(123.45)
var_dump(floatval($number2)); // Output: float(1234.5)

As can be seen from the above example, floatval() can convert a string into Floating point type. Similar to intval(), floatval() returns 0 when the string cannot be converted to a numeric type. It should be noted that due to the precision of floating point numbers, some decimal place errors may occur when using floatval() for addition.

3. doubleval()

doubleval() is similar to floatval(). It is a function in PHP that converts strings to double-precision floating point numbers. Its syntax is:

float doubleval (mixed $var)

Among them, $var represents the string or value that needs to be converted. For example:

$number1 = "123.45";
$number2 = "12.345e2"; // 12.345 x 10^2

var_dump(doubleval($number1)); // Output: float(123.45)
var_dump(doubleval($number2)); // Output: float(1234.5)

As can be seen from the above example, doubleval() can also convert strings into a double precision floating point number type. Similar to floatval(), doubleval() returns 0 when the string cannot be converted to a numeric type.

2. Add numbers

After converting strings into numbers, you can add them. PHP supports addition operations of various numerical types, including integers, floating point numbers, and double-precision floating point numbers. Here is a simple example:

$number1 = "123";
$number2 = "456.78";

$sum = intval($number1) floatval($number2);

var_dump($sum); // Output: float(579.78)

As can be seen from the above example, intval() and floatval() can convert strings into corresponding Numeric types so that they can be added. It should be noted that when two values ​​of different types are added, PHP will automatically convert them to the same type, usually a floating point number. If you want to convert them to an integer type, you can use intval() for conversion.

Summary

In PHP, converting strings into numbers and adding them is a common operation. You can use intval(), floatval(), and doubleval() to convert strings into different types of values ​​such as integers, floating point numbers, and double precision floating point numbers. When adding, you need to pay attention to the conversion and precision of numerical types. By mastering this knowledge, you can easily implement the functions of converting strings to numbers and adding numbers.

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