General Array Usage

An array holds a list of data items sequentially. Typically, these items are selected and accessed via a numeric index.

The program below creates an empty array called: $saDaysOfTheWeek. This array is printed out three times than filled and printed again using the same three methods. After that, we print the size of the array. Then the array is printed three more times in different ways to demonstrate common array usage.

Arrays.php

<?php
  // Arrays (basic operations)
  // Create an empty array and print it in three ways
  $saDaysOfTheWeek = array();
  echo "<b>Three Outputs of an Empty Array:</b><br />";
  echo "<b>print_r():</b> ";
  print_r($saDaysOfTheWeek);
  echo "<br /><b>var_dump():</b> ";
  var_dump($saDaysOfTheWeek);
  echo "<br /><b>var_export():</b> ";
  var_export($saDaysOfTheWeek);
  echo "<br /><br />";

  // Push entries into the array
  array_push($saDaysOfTheWeek, "Monday");
  array_push($saDaysOfTheWeek, "Tuesday");
  array_push($saDaysOfTheWeek, "Wednesday");
  array_push($saDaysOfTheWeek, "Thursday");
  array_push($saDaysOfTheWeek, "Friday");
  array_push($saDaysOfTheWeek, "Saturday");
  array_push($saDaysOfTheWeek, "Sunday");

  // Print the filled array in the same three ways
  echo "<b>Three Outputs of a Filled Array:</b><br />";
  echo "<b>print_r():</b> ";
  print_r($saDaysOfTheWeek);
  echo "<br /><b>var_dump():</b> ";
  var_dump($saDaysOfTheWeek);
  echo "<br /><b>var_export():</b> ";
  var_export($saDaysOfTheWeek);
  echo "<br /><br />";

  // Get the size of the array
  echo "The array has ".count($saDaysOfTheWeek)." entries.<br /><br />";

  // Use a foreach loop to print each entry
  echo "<b>Foreach loop over Days:</b><br />";
  foreach ($saDaysOfTheWeek as $sDay) {
    echo "{$sDay}<br />";
  }
  echo "<br />";

  // Use a foreach loop to print each key with its value
  echo "<b>Foreach loop with Key=>Value Pairs:</b><br />";
  foreach ($saDaysOfTheWeek as $key => $value) {
    echo "{$key} => {$value} ";
  }
  echo "<br /><br />";

  // Use a for loop to print each entry via the index
  echo "<b>For loop with Index Access:</b><br />";
  $iSize = count($saDaysOfTheWeek);
  for ($i = 0; $i < $iSize; ++$i) {
    echo "{$saDaysOfTheWeek[$i]}<br />";
  }
?>

Output