PHP Int

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PHP int, or integer, is a data type that represents whole numbers, such as 1, 100, or -5, without any decimal places. We can use integers in PHP for mathematical operations and for comparing numbers in code.

The term ‘int’ just means integer in PHP, and the two words are permitted to be utilized.

Moreover, there are some constants in PHP that set the limits for integers. These limits include the maximum and minimum values an integer can have.

  • PHP_INT_SIZE keeps track of how many bytes something uses. Simply put, it’s usually 8 bytes.
  • PHP_INT_MAX gives you the largest possible integer value in PHP. It’s a big number: 9223372036854775807.
  • PHP_INT_MIN shows the smallest whole number in PHP, and it’s – 9223372036854775808.

Additionally, remember that the size of a number in PHP depends on the platform you’re using. But generally, it allows for a maximum value of 2 billion to be stored in an integer variable.

Anyway, PHP has 4 integer (int) types, which are:

php integer

Let’s focus on each one in-depth.

Exploring Decimal Numbers in PHP

Basically, numbers with a decimal point are known as decimal numbers. This point, which is usually on the right side of the number, may have one or more digits. Ten is the maximum number of digits in base 10 that come after the decimal point.

To make numbers in PHP simpler to understand, group them together with underscores. For example:

<?php 
   echo 4_487_456 // 4487456 decimal;
   echo 145 // 145 decimal;
?>

Anyway, let’s go on to the next section, where we’ll look at hexadecimal numerals in more depth.

Understanding Hexadecimal Numbers

Typically, hexadecimal refers to base-16 digits between 0 and 15. It deals with single-digit integers ranging from 0 to 9. The extra six digits are replaced with characters in the sequence of ‘a’ to ‘f’ based on their individual records.

The following list shows the double digits that would be used in place of the alphabetical characters:

  • 10 -> a
  • 11 -> b
  • 12 -> c
  • 13 -> d
  • 14 -> e
  • 15 -> f

Hexadecimal numerals represent values beyond single-digit integers using the letters A through F. Understanding the difference between ordinary numbers (0–9) and letters (A–F) is crucial to understanding the system.

To combine letters and numbers, start at the beginning with ‘0x’. For a clear example, see below:

<?php  echo 0x2FD; // decimal 765 ?>

The result in this model is 765. If you go back and read this part again, you will see that we are using base-16 for the hexadecimal scheme. This implies that the calculation will look like the picture below if we want to convert a number from hexadecimal to digits.

hexadecimal numeral system

Explaining the Calculation Process

Check the three numbers with the red circle, from right to left: 0, 1, and 2. These numbers begin with zero and address the kind. For instance, a 162 type denotes 16 x 16, while a 164 type denotes 16 x 16 x 16 x 16, and so on.

Let’s break down the figure line by line, starting from the left.

  • Hexadecimal is represented by adding “0x” to the beginning of numerals.
  • As discussed in the last section, you should enter the numbers in the resultant line, starting with zero and going from right to left.
  • Increase the primary number to (2 x 16)₂ from the left, and it will increase to (2 x (16 x 16). The result is 512.
  • The next number expands to (15 x (16)): (15 x 16) ₁. The result is 240.
  • Then, there is a similar growth in the number (13 x 16) 0. The result is 13.
  • Adding up these red font results gives us the number 765.

You now have a solid understanding of the foundations of working out when dealing with additional PHP number (int) types.

Anyway, let’s move on to octal numbers in PHP.

Octal Numbers in PHP

There is a digit range for octal numbers between (0) and (7), encompassing eight numbers in total (base 8). To define octal numbers, simply add ‘0’ or (‘0o’ for PHP 8.1.0) at the beginning. For example:

<?php 
   echo 0457; // decimal 303 
?>

The figure below provides an explanation and illustrates how to calculate it.

php octal

Explaining the Calculation Process

The number (0457) is an octal representation. In the octal system, the digits extend from (0) to (7). The equivalent decimal value is as follows:

4 * (8^2) + 5 * (8^1) + 7 * (8^0) = 303

Therefore, it will output (303) in decimal notation.

Let’s delve deeper into another type of PHP integer—binary numbers.

Understanding Binary Numbers

The binary number system just uses the (0s) and (1s), which are called binary bits. This system starts with 0s.

Additionally, binary numbers are very important to machine code, which is a basic type of computer language.

In this section, you will cover the number systems and how they would be calculated. Here is an example.

<?php echo 0b101111; // Decimal 47 ?>

The figure below shows how to calculate the binary numeral system.

binary system

So, look at this binary number (0b101111). It starts with the prefix (0b), which indicates that the following digits are in binary notation.

If you focus on the following digits of this prefix (0b), which is (101111), you will see it shows a series of powers of (2), like the one below.

(1) x ((2 ^ 0) = ( 1 ) = (1)) = 1
(1) x ((2 ^ 1) = ( 2 ) = (2)) = 2
(1) x ((2 ^ 2) = ( 2 x 2 ) = (4)) = 4
(1) x ((2 ^ 3) = ( 2 x 2 x 2) = (8)) = 8
(0) x ((2 ^ 4) = ( 2 x 2 x 2 x 2 ) = (16)) = 0
(1) x ((2 ^ 5) = ( 2 x 2 x 2 x 2 x 2) = (32)) = 32

Here is an analysis of the above calculation.

  • The rightmost digit is (1), which represents (2 ^ 0), so usually the first digit in the right position is (1).
  • In the next number, the digit is (1), so it exposes the exponentiation like this: (2 ^ 1) = (2).
  • We are still moving from right to left in the calculation. The next digit is (1), which is the number (2) that equals (2 ^ 2) = (4).
  • And then the following number is (1), which would take (2 ^ 3) = (8).
  • The next digit is 0, representing (2^4). Since this digit is (0), it contributes (0) to the total.
  • In the final digit, which is the most left number, it is (1). It takes (2^5), and that equals (32).

Let’s get the sum of the whole calculated number:

32 + 0 + 8 + 4 + 2 + 1 = 47

So, (0b101111) in binary is equal to (47) in decimal.

Checking if a Value is an Integer: "is_int()"

Ever want to make sure your value is truly an integer? PHP has a function that does just that: it's called is_int(). It's like having a double-check in your back pocket.

$age = 18;

if (is_int($age)) {
    echo "Yep, it’s an integer!";
} else {
    echo "Nope, that’s not an integer.";
}

In the above example, is_int($age) checks whether the variable $age is an integer. As 18 is a whole number, PHP returns "Yep, it's an integer!".

Type Casting: Switching to Integers

Let’s say you have a float (like 5.7) but want to turn it into an integer. Type casting is your friend here. It’s a way to tell PHP, “Hey, treat this number as a whole number, please.”.

$decimal = 5.7;
$integer = (int)$decimal;

echo $integer; // Output: 5

By using (int), PHP drops the decimal part, leaving just 5. This is great when you’re working with mixed number types and want to ensure they’re integers.

Overflow and Limits in PHP Integers

PHP integers have their limits, and if you exceed them, PHP converts the number to a float. It’s called integer overflow, and here’s what it looks like:

$bigNumber = 2147483647;
$bigNumber += 1;

echo $bigNumber; // Could become a float if it exceeds max limit

In this case, $bigNumber hits the maximum integer range for a 32-bit system. Once you go beyond that, PHP says, “Alright, let’s switch this to a float.”.

Wrapping UP

In this tutorial, you learned what PHP (int) integers are, including their types such as decimal, hexadecimal, octal, and binary. We started with an explanation of the basics of each type, with examples that exposed some techniques for calculations.

So, in the first section, we discuss PHP_INT_SIZE, PHP_INT_MAX, and PHP_INT_MIN constants. These help you understand the size limits of PHP numbers.

And then you understood the decimal numbers and how they work in PHP.

In the following section, we explored the hexadecimal numbers, and you learned what they look like and how to convert them to decimals.

Then, we explained what octal numbers are and how to use them in PHP with real examples.

In this tutorial, you also got an understanding of what binary numbers are and learned about their importance in computer computing.

Thank you for reading. Happy Coding!

Frequently Asked Questions (FAQs)

  • What is an integer (int) in PHP?

    An integer in PHP, or int, is a data type representing whole numbers without any decimal points. Examples include 1, -100, and 42.

  • How do I check if a variable is an integer in PHP?

    To check if a variable is an integer, you can use the is_int() function. It returns true if the variable is an integer and false otherwise. Example: 
    $age = 18;
if (is_int($age)) {
    echo "Yes, it’s an integer!";
} else {
    echo "No, not an integer.";
}

  • What are the different integer types in PHP?

    PHP integers can be represented in four different types based on the number system used: decimal (base-10), hexadecimal (base-16), octal (base-8), and binary (base-2). Each type is useful for specific calculations or coding practices.

  • What is PHP_INT_MAX, and how is it used?

    PHP_INT_MAX is a PHP constant that provides the largest possible integer value your PHP installation can handle. You can use it to check if a number exceeds the maximum limit, which would convert it to a float automatically. Example: 
    echo PHP_INT_MAX; // Outputs the maximum integer, e.g., 9223372036854775807 on a 64-bit system

  • How does PHP handle integer overflow?

    If an integer exceeds PHP_INT_MAX, PHP will automatically convert it to a float, as integers have a maximum and minimum range limit.

  • What’s the difference between decimal, hexadecimal, octal, and binary in PHP?

    - Decimal numbers use base-10, ranging from 0 to 9. - Hexadecimal numbers use base-16, ranging from 0 to 15 (with 10-15 represented by a to f). - Octal numbers use base-8, ranging from 0 to 7. - Binary numbers use base-2, with only 0 and 1. Each system is useful for different programming needs, such as working with bitwise operations or specific numbering formats.

  • How can I convert a decimal to hexadecimal in PHP?

    To convert a decimal to hexadecimal, use the dechex() function. Example: 
    $decimal = 255;
$hexadecimal = dechex($decimal);
echo $hexadecimal; // Outputs "ff"

  • How does PHP interpret large integers, and when does it switch to floats?

    PHP interprets integers within a specific range based on the system (32-bit or 64-bit). When an integer exceeds this range, PHP converts it to a float to handle the larger value.

  • What’s the purpose of PHP_INT_SIZE in PHP?

    PHP_INT_SIZE is a constant that shows the number of bytes used to store an integer on your system. Typically, it’s 4 bytes on 32-bit systems and 8 bytes on 64-bit systems.

  • How do I define an octal number in PHP?

    To define an octal number, prefix it with 0 or 0o (in PHP 8.1.0 and later). Example: 
    $octal = 0457; // Represents 303 in decimal
echo $octal;

  • What is binary in PHP, and how is it used in calculations?

    Binary numbers in PHP are represented with the prefix 0b, and they only contain 0s and 1s. Binary numbers are particularly useful for low-level programming, like bitwise operations. Example: 
    $binary = 0b1011; // Represents 11 in decimal
echo $binary;

  • How can I convert a float to an integer in PHP?

    You can convert a float to an integer using type casting (int). Example: 
    $float = 5.75;
$integer = (int)$float;
echo $integer; // Outputs 5

  • What are the maximum and minimum integer values in PHP?

    PHP_INT_MAX gives you the maximum integer value, and PHP_INT_MIN gives you the minimum integer value. These constants are helpful when checking for potential overflows. Example: 
    echo PHP_INT_MAX; // Outputs the max integer
echo PHP_INT_MIN; // Outputs the min integer

  • How can I use underscores in PHP integers?

    In PHP 7.4 and above, you can use underscores to make large integers more readable. These underscores are ignored by PHP. Example: 
    $number = 1_000_000; // Same as 1000000
echo $number;

  • Why does PHP convert integers to floats on overflow?

    When an integer exceeds PHP_INT_MAX, PHP can’t store it as an integer and automatically converts it to a float to accommodate the larger number.

  • How does PHP handle numbers in different bases (like octal and binary)?

    PHP supports integers in decimal (default), octal (prefix 0), hexadecimal (prefix 0x), and binary (prefix 0b). PHP interprets each based on its prefix and uses them for various calculations.

  • What is the modulus operator (%) in PHP, and how does it work with integers?

    The modulus operator % returns the remainder of a division operation. It’s commonly used to check if a number is even or odd. Example: 
    $number = 7;
echo $number % 2; // Outputs 1, so 7 is odd

  • What is integer type casting in PHP?

    Type casting in PHP converts a variable from one type to another. For integers, you can cast a variable as an integer using (int).

  • Why use `is_int()` in PHP?

    is_int() checks if a value is an integer, helping ensure you’re working with the expected data type in conditions or calculations.

  • How do I perform calculations with integers in PHP?

    PHP supports basic arithmetic operations with integers, such as addition, subtraction, multiplication, and division. Example: 
    $a = 10;
$b = 5;
echo $a + $b; // Addition
echo $a - $b; // Subtraction
echo $a * $b; // Multiplication
echo $a / $b; // Division
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