(int) is the fastest and non-destructive, ideal for simple conversions without altering the original variable. 2. intval() provides base conversion support and is slightly slower but useful for parsing hex or binary strings. 3. settype() permanently changes the variable’s type, returns a boolean, and is slowest, best for in-place data normalization. All three truncate rather than round and parse leading digits from strings, so choose based on need: speed with (int), control with intval(), or mutation with settype().

When working with type handling in PHP, converting values to integers is a common task. While PHP is loosely typed, there are times when you need to explicitly ensure a value is an integer. Three common ways to achieve this are using the (int) cast, the intval() function, and settype(). Though they may seem similar at first glance, they behave differently in important ways. Let’s break down each method and compare them in terms of functionality, performance, and use cases.

1. (int) — Type Casting

The (int) construct is a type cast that converts a value to an integer at the moment of evaluation.

$var = "123abc";
$int = (int)$var; // 123

Key Characteristics:

• Non-destructive: It doesn't change the original variable.
• Immediate conversion: Returns a new integer value.
• Truncates on strings: Parses the string from the start until a non-numeric part (no rounding).
• Fastest method: Done at the language level, so it's generally the most performant.

Examples:

(int)"42"       → 42
(int)"42.99"    → 42   (truncates, not rounded)
(int)"42abc"    → 42   (stops at first invalid char)
(int)[]         → 0    (empty array → 0)
(int)[1,2]      → 1    (array → 1 if non-empty)

? Best for: Simple, fast conversions when you don’t need to modify the original variable.

2. intval() — Integer Value Function

intval() is a function that converts a value to an integer, with an optional base parameter (e.g., binary, hex).

$int = intval("123abc"); // 123
$hex = intval("FF", 16); // 255

Key Characteristics:

• Also non-destructive: Returns a new integer.
• Supports base conversion: Can interpret strings in different number bases.
• Similar truncation behavior: Like (int), it reads from the beginning until invalid characters.
• Slightly slower: Function call overhead makes it less efficient than casting.

Examples:

intval("42")        → 42
intval("42.99")     → 42
intval("42abc")     → 42
intval("0xFF", 16)  → 255
intval(true)        → 1

? Best for: When you need base conversion (e.g., hex, binary) or more readable, explicit type conversion in code.

3. settype() — In-Place Type Change

settype() modifies the original variable by changing its type and value.

$var = "123abc";
settype($var, 'integer'); // $var is now 123 (integer)

Key Characteristics:

• Destructive: Alters the original variable.
• Returns boolean: true on success, false on failure.
• Less predictable: Behavior varies more with complex types.
• Slowest: Involves runtime type mutation.

Examples:

$var = "42";
settype($var, 'integer'); // $var = 42 (int)

$var = "42.99";
settype($var, 'integer'); // $var = 42

$var = "abc";
settype($var, 'integer'); // $var = 0

? Best for: Situations where you want to permanently change a variable’s type, such as sanitizing input in place.

Comparison Summary

Practical Recommendations

• Use (int) when:

  • You want a fast, clean cast.
  • You're doing math or comparisons and just need an int.
  • You don’t want to alter the original variable.

• Use intval() when:

  • You're parsing user input that might be in hex (0xFF) or binary.
  • You want more control via base parameter.
  • You prefer function-based clarity.

• Use settype() when:

  • You’re normalizing data in an array or object and want to mutate values.
  • You’re building a data processing pipeline and need to enforce types.

Final Note

All three methods truncate, not round. So (int)4.9 gives 4, not 5. If you need rounding, use round() first.

Also, be cautious with malformed strings — all three will extract leading digits and ignore the rest, which may hide bugs.

Bottom line: (int) is usually best for performance and simplicity. intval() wins when you need flexibility. settype() is niche, but useful when in-place mutation is desired.

Basically, choose based on whether you want speed, control, or mutation.

The above is the detailed content of A Comparative Analysis: `(int)` vs. `intval()` and `settype()`. For more information, please follow other related articles on the PHP Chinese website!