Ruby cheatsheet for array
Remove nil items
[nil, 'apple', 'orange', '', 'banana'].compact => ["apple", "orange", "", "banana"]
Remove empty items
[nil, 'apple', 'orange', '', 'banana'].compact_blank => [nil, "apple", "orange", "banana"]
Remove nil & empty items
[nil, 'apple', 'orange', '', 'banana'].reject(&:blank?) => ["apple", "orange", "banana"]
Return common items
[1, 2, 3] & [2, 3, 4] => [2, 3]
Return different items
a = [1, 2, 3] b = [2, 3, 4] a - b | b - a => [1, 4]
Joining arrays without duplication
[1, 2, 3] | [2, 3, 4] => [1, 2, 3, 4]