PHP: Indexed Arrays III

Derek Bridge

Department of Computer Science,
University College Cork

PHP: Indexed Arrays III

Aims:

• to practice writing PHP for processing indexed arrays

Another built-in function

• We'll need this later today: isset($v), which returns true if $v is non-null; false otherwise
• Class exercise: Suppose we do this:

  $x = 3;
  $y = NULL;

• Which of these returns true, and which false?
  1. isset( $x )
  2. isset( $y )
  3. isset( $z )

Class exercises

1. Given a value $val, write some PHP which echoes 'Yes' if $val is in an array called $a, and 'No' otherwise (using == to test for equality)
2. Write some PHP to find and echo the smallest number in the array of integers called $a
3. Write some PHP to find and echo the largest number in the array of positive integers called $a

A remark

In fact, there are built-in functions for each of the above, so we didn't need to write our own PHP:

1. in_array( $val, $array )
2. min( $array )
3. max( $array )