> ## Documentation Index
> Fetch the complete documentation index at: https://docs.syntblaze.com/llms.txt
> Use this file to discover all available pages before exploring further.
# PHP true
In PHP, `true` is a reserved keyword and a boolean literal representing the affirmative truth state in boolean logic. It is one of the two possible states of the scalar `bool` data type, the other being `false`.
## Syntax and Case Sensitivity
The `true` literal is case-insensitive. However, the PHP-FIG PSR-12 coding standard mandates the use of strictly lowercase letters for all reserved keywords, including boolean literals.
```php theme={"dark"}
$a = true; // Standard (PSR-12 compliant)
$b = TRUE; // Valid, but non-standard
$c = True; // Valid, but non-standard
var_dump($a === $b); // bool(true)
```
## Type Coercion and Casting
When PHP's Zend Engine coerces or explicitly casts the `true` literal into other scalar or compound types, it follows strict internal conversion rules:
* **Integer:** Casts to `1`.
* **Float:** Casts to a floating-point `1.0` (Note: `var_dump` outputs whole-number floats without the `.0` decimal).
* **String:** Casts to `"1"` (Note: `false` casts to an empty string `""`).
* **Array:** Casts to an indexed array containing the boolean as its single element at index `0`.
```php theme={"dark"}
var_dump((int) true); // int(1)
var_dump((float) true); // float(1)
var_dump((string) true); // string(1) "1"
var_dump((array) true); // array(1) { [0]=> bool(true) }
```
## Comparison Mechanics
Because PHP is a dynamically typed language, `true` behaves differently depending on whether an equality (`==`) or identity (`===`) operator is used.
Under loose comparison (`==`), PHP performs type juggling, coercing operands to booleans. Specific "falsy" values—such as `0`, `0.0`, `"0"`, `""`, `null`, and empty arrays `[]`—evaluate to `false`, while most other values evaluate to `true`. Under strict comparison (`===`), no type coercion occurs; the operand must be of type `bool` and hold the exact value of `true`.
```php theme={"dark"}
// Loose comparison (Type juggling occurs)
var_dump(true == 1); // bool(true)
var_dump(true == "1"); // bool(true)
var_dump(true == "hello"); // bool(true)
var_dump(true == "0"); // bool(false)
// Strict comparison (Type and value must match)
var_dump(true === 1); // bool(false)
var_dump(true === true); // bool(true)
```
## Type Verification
To programmatically verify if a variable holds the exact boolean `true` state, strict comparison (`===`) is required. Relying solely on type-checking functions like `is_bool()` is insufficient, as it only verifies the data type and will return `true` even if the variable holds `false`.
```php theme={"dark"}
$value = true;
var_dump(is_bool($value)); // bool(true) - Only confirms type (could be false)
var_dump($value === true); // bool(true) - Confirms both type and state
```
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