> ## 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 If Statement
The `if` statement is a fundamental control flow structure in PHP that dictates the conditional execution of a code block based on the evaluation of a specified expression. If the expression evaluates to `true`, the nested statement or code block is executed; if it evaluates to `false`, the execution bypasses the block.
## Standard Syntax
PHP utilizes C-style syntax for standard control structures, enclosing the conditional expression in parentheses and the executable block in curly braces.
```php theme={"dark"}
if (expression) {
// statement(s) to execute if expression evaluates to true
}
```
If only a single statement is to be executed, the curly braces can technically be omitted. However, modern PHP coding standards (such as PER/PSR-12) mandate the use of curly braces for all control structures to prevent scope-related bugs during maintenance.
```php theme={"dark"}
// Valid, but discouraged by coding standards
if (expression)
statement;
```
## Expression Evaluation and Type Juggling
The `expression` inside the `if` statement does not need to be a strict boolean type. PHP utilizes implicit type casting (type juggling) to evaluate the expression in a boolean context.
The following values are implicitly cast to `false` (often referred to as "falsy" values):
* The boolean `false` itself
* The integer `0` (zero)
* The float `0.0` (zero)
* The empty string `""`, and the string `"0"`
* An array with zero elements `[]`
* The special type `NULL` (including unset variables)
* SimpleXML objects created from empty tags
Any value not strictly matching the list above evaluates to `true`.
## Branching: `else` and `elseif`
The `if` statement can be extended using `else` to define a fallback block when the initial expression evaluates to `false`, and `elseif` to evaluate subsequent conditions.
```php theme={"dark"}
if (expression1) {
// executed if expression1 is true
} elseif (expression2) {
// executed if expression1 is false and expression2 is true
} else {
// executed if all preceding expressions are false
}
```
*Note:* PHP accepts both `elseif` (single word) and `else if` (two words) when using curly braces. The parser treats them identically in this context.
## Alternative Syntax
PHP provides an alternative syntax for control structures, which is primarily utilized within view templates mixed with HTML. This syntax replaces the opening curly brace with a colon (`:`) and the closing curly brace with the `endif;` keyword.
```php theme={"dark"}
if (expression1):
// statement(s)
elseif (expression2):
// statement(s)
else:
// statement(s)
endif;
```
*Crucial Distinction:* When using the alternative syntax, you **must** use the single-word `elseif`. Using the two-word `else if` with the colon syntax will result in a parse error.
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