array

  • There are many ways to create an array in PHP using the array function. It is important to remember that Ruby uses both Array and Hash objects to implement the various functionality of PHP arrays. See Array for more details.

    Ordered Arrays

    Only numerically indexed arrays are ordered in Ruby. We can create a numerically indexed array a few different ways. The most popular is using square brackets with comma separated list. An alternate syntax is to use %w{} to build an array out of a list of words.

    Notice that Ruby does not store a numbered index like the PHP array. Ruby arrays are a simple stack where index is determined by position only. You cannot skip elements in a Ruby array.

    PHP

    array = array('chicago', 'london', 'paris');
var_export($array);
// => array(0 => 'chicago', 1 => 'london', 2 => 'paris')

    Ruby

    array = ["chicago", "london", "paris"]
# or
array = %w{ chicago london paris }
 
p array
# => ["new york", "london", "paris"]

    Associative Arrays

    We create associative arrays in Ruby using hashes. The most common syntax to create a hash in Ruby is using curly braces with a comma separated list of key value pairs.

    In Ruby we’ll typically use symbols for the keys of our hashes instead of a string. Symbols are a lightweight replacement for strings when you simply need to name something, and don’t need a full string object. This tends to be the case most of the time when we are creating a hash. We simply need a label or name to use when referring back to a value in the hash.

    Remember that hashes are unordered collections. You must use a Ruby array object if you need an ordered collection.

    PHP

    $array = array('age' => 26, 'name' => 'Joe', 'country' => 'USA');
var_export($array);
// => array('age' => 26, 'name' => 'Joe', 'country' => 'USA')

    Ruby

    p {:age => 26, :name => "Joe", :country => "USA"}
# => {:age=>26, :country=>"USA", :name=>"Joe"}

    Mixed Arrays

    We can create collections with a mix of numeric and string based keys in Ruby using hashes. PHP automatically assigns a numeric index to elements without a specified key. Ruby is different in that it requires you to specify the key value on every element.

    PHP

    $array = array('age' => 25, 1, 'name' => 'Joe', 2);
var_export($array);
// => array('age' => 25, 0 => 1, 'name' => 'Joe', 1 => 2)

    Ruby

    hash = {:age => 25, 0 => 1, :name => "Joe", 1 => 2}
p hash
# => {0=>1, :age=>25, 1=>2, :name=>"Joe"}

    see also

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