Basic: Array
Seringkali belajar dengan melihat( dan mempraktikkan) contoh itu membuat saya (kita?) lebih mudah memahami suatu konsep. Agree? 
Contoh 1:
a = [ 3.14159, "pie", 99 ] a.class # => Array a.length # => 3 a[0] # => 3.14159 a[1] # => "pie" a[2] # => 99 a[3] # => nil
Contoh 2:
b = Array.new b.class # => Array b.length # => 0 b[0] = "second" b[1] = "array" b # => ["second", "array"]
Pada ruby, index array dimulai dari 0. Juga dikenal index dengan angka negatif, yg berarti index dihitung dari posisi paling belakang. Lihat contoh aja, biar lebih mudah dimengerti:
Contoh 3:
a = [ 1, 3, 5, 7, 9 ] a[-1] # => 9 a[-2] # => 7 a[-99] # => nil
array index
Contoh 4 – mengambil beberapa elemen array:
a = [ 1, 3, 5, 7, 9 ] a[1, 3] # => [3, 5, 7] a[3, 1] # => [7] a[-3, 2] # => [5, 7]
Contoh 5 – range indexing:
a = [ 1, 3, 5, 7, 9 ] a[1..3] # => [3, 5, 7] a[1...3] # => [3, 5] a[3..3] # => [7] a[-3..-1] # => [5, 7, 9]
Contoh 6 – Mereplace elemen array
a = [ 1, 3, 5, 7, 9 ] # => [1, 3, 5, 7, 9] a[1] = ’bat’ # => [1, "bat", 5, 7, 9] a[-3] = ’cat’ # => [1, "bat", "cat", 7, 9] a[3] = [ 9, 8 ] # => [1, "bat", "cat", [9, 8], 9] a[6] = 99 # => [1, "bat", "cat", [9, 8], 9, nil, 99]
Contoh 7 – Mereplace / menambahkan elemen array
a = [ 1, 3, 5, 7, 9 ] # => [1, 3, 5, 7, 9] a[2, 2] = ’cat’ # => [1, 3, "cat", 9] a[2, 0] = ’dog’ # => [1, 3, "dog", "cat", 9] a[1, 1] = [ 9, 8, 7 ] # => [1, 9, 8, 7, "dog", "cat", 9] a[0..3] = [] # => ["dog", "cat", 9] a[5..6] = 99, 98 # => ["dog", "cat", 9, nil, nil, 99, 98]
Contoh 8 – Beberapa array method
# method push untuk menambah elemen array. # method pop untuk mengambil elemen array dari belakang stack = [] stack.push "red" stack.push "green" stack.push "blue" p stack # => ["red", "green", "blue"] puts stack.pop # => blue puts stack.pop # => green puts stack.pop # => red p stack # => [] #method shift untuk mengambil elemen array dari depan queue = [] queue.push "red" queue.push "green" p queue # => ["red","green"] puts queue.shift # => red puts queue.shift # => green p queue # => [] array = [ 1, 2, 3, 4, 5, 6, 7 ] p array.first(4) # => [1, 2, 3, 4] p array.last(4) # => [4, 5, 6, 7] p array # => [1, 2, 3, 4, 5, 6, 7]
Okey, saatnya buka irb dan….happy coding.
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