Hashtables

Hashtables are one of the most important structures used by PHP. They form the basis for arrays, object properties, symbol tables and have countless other applications throughout the engine. This chapter will introduce how hashtables work and cover the related APIs in detail.

Contents:

• Basic structure
  • Basic concepts
  • The HashTable and Bucket structures
• Hashtable API
  • Creating and destroying hashtables
  • Integer keys
  • String keys
  • Apply functions
  • Iteration
  • Copying and merging
  • Comparison, sorting and extrema
• Symtable and array API
  • Symtables
  • Array API
• Hash algorithm and collisions
  • Analyzing collisions
  • Index collisions
  • Hash collisions