PHP
Syntax
PHP executes statements inside PHP tags; statements end with semicolons.
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PHP
23 practical topics
PHP
Types
PHP has scalar, compound, and special types.
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Variables
Variables begin with $ and can hold different values over time.
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Arrays
Arrays are ordered key/value maps.
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Filtering and sorting
Filter selects values; sorting changes their order.
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Strings
Strings contain bytes; concatenation uses a dot.
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Functions
Functions give a named operation explicit inputs and a return value.
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Classes
Classes combine behavior with state.
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Interfaces
An interface defines a contract that implementations must satisfy.
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Traits
Traits reuse method implementations across classes.
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Enums
Enums define a closed set of named values.
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Constructors
A constructor initializes an object; promotion declares and assigns properties.
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Visibility
public, protected, and private control access to members.
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Static
Static members belong to the class rather than an instance.
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Exceptions
Exceptions interrupt execution until caught; Throwable covers Error and Exception.
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Namespaces
Namespaces avoid name collisions and organize symbols.
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Closures
Closures are anonymous functions that can capture outer values.
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Anonymous functions
Arrow functions express one expression and capture outer variables by value.
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Type declarations
Parameter, property, and return types express allowed values.
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Null handling
?? supplies a default for absent/null values; ?-> stops a chain on null.
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Match expressions
match returns a value using strict comparisons.
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Common standard-library functions
Standard functions handle common collection, JSON, date, and validation tasks.
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PDO prepared statements
PDO provides parameterized database access in plain PHP.