PHP int vs integer:What is the difference between int and integer in PHP type declarations?

Q: What is the difference between int and integer in PHP type declarations?

A: In PHP, int and integer are aliases for the same scalar type, but int is the canonical name used in type declarations, while integer is accepted mainly for historical compatibility. Since PHP 7.0, scalar type declarations support int, and PHP 8.0 expanded support for union types such as int|string. The official PHP 2026 migration and language reference documentation continues to recommend int in new code because it matches reflection output and modern static analysis expectations. Using integer in a type declaration may still work, but int is clearer and more consistent. For example, function add(int $a, int $b): int is preferred over using integer. To check a value, is_int() is the standard function, while is_integer() is an alias. Both return true for integer values, but int is the primary form in the PHP manual and PHP 2026 coding standards.

Q: Is integer a valid type declaration in PHP 2026?

A: Yes, integer remains a valid alias for int in PHP type declarations as of PHP 8.x and the 2026 PHP language reference, but its use is discouraged. The PHP manual lists int as the canonical scalar type and notes that integer is an alias accepted for backward compatibility. In practice, function foo(integer $x) may parse and behave like foo(int $x), but static analyzers and IDEs often flag integer as non-standard. PHP’s official 2026 migration guides emphasize using int for parameters, return types, and property types because it is what ReflectionType returns and what tools expect. Additionally, PHP 8.0+ union types require int, not integer, for example int|string. Therefore, while integer is technically valid, modern PHP 2026 code should use int for clarity, tooling support, and consistency with the official documentation.

Q: Why does PHP have both int and integer?

A: PHP has both int and integer mainly because of historical naming and backward compatibility. Early PHP versions used integer in documentation and function names such as is_integer(), while the internal type name and later scalar type declarations standardized on int. When PHP 7.0 introduced scalar type declarations, int became the canonical type name, and integer was retained as an alias to avoid breaking older code. The PHP 2026 manual still documents is_integer() as an alias of is_int(), reflecting this dual naming. Similarly, settype($var, 'integer') and settype($var, 'int') both work, but int is preferred. The PHP 2026 coding standards and migration reports recommend int for new declarations, casting, and reflection checks. This dual naming is a compatibility layer rather than two distinct types; both refer to the same 64-bit or platform-dependent integer type.

Q: Should I use int or integer in PHP 2026 coding standards?

A: You should use int in PHP 2026 coding standards and type declarations. The official PHP manual identifies int as the canonical name for integer values, and PHP 8.x reflection returns int rather than integer. Major PHP 2026 style guides, including PSR-12 and framework standards, expect int for parameter types, return types, and property types. Using int also works correctly with union types like int|float and nullable types like ?int, while integer is not consistently supported in those contexts. For runtime checks, is_int() is preferred over is_integer(), though both are functionally equivalent. The settype() function accepts both 'int' and 'integer', but official examples in the PHP 2026 documentation use 'int'. In summary, choose int for declarations, casts, and checks to align with PHP’s current language reference, static analysis tools, and the broader PHP 2026 ecosystem.

Dialogue about

Common scenarios of "PHP int vs integer"

【Student】 Hey, I'm a bit confused about PHP's int and integer. Are they the same thing?

【Teacher】 Great question! In PHP, 'int' and 'integer' are actually two names for the same type. They are aliases. So when you use 'int' or 'integer' in type declarations, they refer to the same thing.

【Student】 So there's no difference at all? Why do both exist then?

【Teacher】 Historically, PHP had 'integer' as the type name, but later introduced 'int' as a shorter alias. Both are accepted, but 'int' is more modern and preferred in most coding standards.

【Student】 So if I write a function with parameter type 'integer', it will work the same as 'int'?

【Teacher】 Exactly. For example, function foo(integer $x) and function foo(int $x) are equivalent. However, note that 'integer' as a type declaration is only supported in PHP 7.0 and later? Actually, both were introduced in PHP 7.0. But 'int' is more commonly used.

【Student】 What about type casting? Is (integer) the same as (int)?

【Teacher】 Yes, (int) and (integer) casts are identical. They both convert a value to an integer. You can use either, but (int) is shorter and more common.

【Student】 Are there any cases where one is preferred over the other?

【Teacher】 In modern PHP code, especially following PSR standards, 'int' is preferred for type hints and casts because it's concise. However, using 'integer' is not wrong; it's just less common.

【Student】 What about the is_int() and is_integer() functions? Are they also aliases?

【Teacher】 Yes, is_int() and is_integer() are aliases. Both check if a variable is an integer. Similarly, is_long() is another alias. But is_int() is the most commonly used.

【Student】 So there's no performance difference between using int and integer?

【Teacher】 No, there is no performance difference. They compile to the same internal type. The only difference is in readability and convention.

【Student】 Are there any other aliases for integer in PHP?

【Teacher】 Yes, 'long' is also an alias for integer in some contexts, like in the is_long() function and (long) cast. But 'long' is less used in modern PHP. The main aliases are int, integer, and long.

【Student】 So if I see 'integer' in old code, it's safe to replace with 'int'?

【Teacher】 Generally, yes. But be careful if the code is targeting very old PHP versions (pre-7.0) where 'int' might not be supported as a type declaration. However, for casts and functions, both have been around for a long time.

【Student】 What about return type declarations? Can I use 'integer' as a return type?

【Teacher】 Yes, you can use 'integer' as a return type in PHP 7.0+. But again, 'int' is more conventional. Just be consistent within your codebase.