Educator

Introduction to Conditional Loops

• A while loop is a conditional control structure that executes a statement group repeatedly as long as its specified test condition remains TRUE .
• A while loop’s test condition’s value is compared to TRUE before each execution of the loop’s statement group.
• 'Looping over arrays' is a common programming function, and PHP provides several built-in functions for doing so. They work on the basis of an array cursor , which is a 'marker' for the 'current' array element:
  • current() – returns the value of the array element at the current array cursor position
  • key() – returns the key of the array element at the current array cursor position
  • next() – advances the array cursor by one
  • prev() – moves the array cursor back by one
  • reset() – sets the array cursor to the 1st element
  • end() – sets the array cursor to the last element
• The list() construct and the each() function are also used to loop over arrays.
• list() is used to assign values to multiple variables at a time from an indexed array.
• each() returns key/value information for the current array element in an array and advances the array cursor by one. It returns FALSE if the end of the array is reached.
• Unlike some programming languages, PHP does not have ‘block-level’ scope used with control structures.
• Additional Resources:
  • PHP Manual - while Loop
  • Function Reference - Array Traversal Functions
  • Function Reference - list() Construct
  • Function Reference - each()