PHP Basics

Functions

Data Format & Types

• Syntax
• Operators
• Variables
• Control Structures
• Language Constructs and Functions
• Namespaces 
• Extensions
• Config
• Performance/bytecode caching

• Arguments
• Variables
• References
• Returns
• Variable Scope
• Anonymous Functions, closures

• XML Basics
• SimpleXML
• XML Extension
• Webservices Basics
• SOAP
• JSON 
• DateTime 
• DOMDocument

Web Features

Object Oriented Programming

Security

• Sessions
• Forms
• GET and POST data
• Cookies
• HTTP Headers
• HTTP Authentication
• HTTP Status Codes 

I/O

• Files
• Reading
• Writing
• File System Functions
• Streams
• Contexts

• Instantiation
• Modifiers/Inheritance
• Interfaces
• Return Types
• Autoload
• Reflection
• Type Hinting
• Class Constants
• Late Static Binding
• Magic (_*) Methods
• Instance Methods & Properties
• SPL
• Traits 

• Configuration
• Session Security
• Cross-Site Scripting
• Cross-Site Request Forgeries
• SQL Injection
• Remote Code Injection
• Email Injection
• Filter Input
• Escape Output
• Encryption, Hashing algorithms
• File uploads
• PHP Configuration
• Password hashing API 

Strings & Patterns

Databases & SQL

Arrays

• Quoting
• Matching
• Extracting
• Searching
• Replacing
• Formatting
• PCRE
• NOWDOC
• Encodings

• SQL
• Joins
• Prepared Statements
• Transactions
• PDO

• Associative Arrays
• Array Iteration
• Array Functions
• SPL, Objects as arrays 
• Casting

Error Handling

• Handling Exceptions
• Errors
• Throwables