Week 3 - Day 5 - Playing with Arrays

arrays.php

<?php
/**
 * Playing with Arrays
 * List of functions: http://us2.php.net/manual/en/ref.array.php
 **/
 
// Creating an array
$array = array('value1', 2, 'value3', 4.5);

// Remember an array starts at position 0
// Printing the contents of an array
print_r($array);

// That will give us something like:
// Array ( [0] => value1 [1] => 2 [2] => value3 [3] => 4.5 )
// As you can see it begins at 0 and not 1

// How do access a specific value?
echo $array[2]; // returns value3

// Looping through an array
foreach($array AS $value){
    echo $value . '<br />';
    // will echo value1 then 2, then value3 and then 4.5 separated by a break
}

// How many items are in an array?
echo count($array); // 4

// How do I store data under a string?
$newArray = array('key' => 'value', 'key2' => 'value2');

// Now how would I get 'value2' to show on my screen?
echo $newArray['key2'];

// How would I replace value2 with something else?
$newArray['key2'] = 'something else';

// Checking if an item exists in an array
$names = array('Marcus', 'Tom', 'Jerry');

if( in_array('Jeff', $names) ){
    echo 'Jeff is in the array!';
}else {
    echo 'Jeff is not in the array!';
    // he is not so this will be shown
}

// Get rid of the last item on an array
$lastName = array_pop($names); // $lastName contains 'Jerry'
// using print_r on $names will only show you Marcus and Tom now

// Add an item to the back of an array
array_push($names, 'Jerry'); // yay Jerry is back!
// or...
$names[] = 'Jeff'; // Jeff is in our array now!

// Our array is now: Marcus, Tom, Jerry, Jeff

// Reverse the order of the array
$reversed = array_reverse($names); // Jeff, Jerry, Tom, Marcus

// Sort a bunch of numbers
$numbers = array(7, 4, 1, 3, 6);

sort($numbers);
print_r($numbers); // 1, 3, 4, 6, 7
rsort($numbers); // High to low!
print_r($numbers); // 7, 6, 4, 3, 1

// How about sorting names with mixed cases?
$newNames = array('Cheryl', 'Bob', 'bernie', 'Amanda');

natcasesort($newNames);
print_r($newNames); // Amanda, bernie, Bob, Cheryl

// Let's shuffle an array!
shuffle($newNames);
print_r($newNames); // could return: Bob, Amanda, Cheryl, bernie

// Calculate the sum of all numbers in an array
$numberList = array(1, 8, 13, 6, 5); // why do 1 + 8 + 13 + 6 + 5

echo array_sum($numberList); // 33

// Merge multiple arrays?
$fruits = array('a' => 'apple', 'b' => 'banana', 'c' => 'canteloupe');
$veggies = array('z' => 'zucchini', 'y' => 'yam', 's' => 'shallot');

$fruitsAndVeggies = array_merge($fruits, $veggies);
print_r($fruitsAndVeggies);
// a => apple, b => banana, c => canteloupe, z => zucchini, y => yam, s => shallot

// Apply a function to an array
$lowercased = array('these', 'words', 'are', 'all', 'lowercased');
$uppercased = array_map('strtoupper', $lowercased);

print_r($uppercased); //  THESE, WORDS, ARE, ALL, LOWERCASED

?>