Array Ruby

Estimated reading time: 2 minutes

Array

arr = [1, 2, 3, 4, 5, 6]
arr.first #=> 1
arr.last  #=> 6
arr[2]    #=> 3
arr[100]  #=> nil
arr[-3]   #=> 4
arr[2, 3] #=> [3, 4, 5]
arr[1..4] #=> [2, 3, 4, 5]
arr[1..-3] #=> [2, 3, 4]
arr.take(3) #=> [1, 2, 3]
arr.drop(3) #=> [4, 5, 6]
arr.include?(7) #=> false
arr.push(5) #=> [1, 2, 3, 4, 5]
arr << 6    #=> [1, 2, 3, 4, 5, 6]

looping array

arr = [1, 2, 3, 4, 5]
arr.each { |a| print a -= 10, " " }
# prints: -9 -8 -7 -6 -5
#=> [1, 2, 3, 4, 5]

combining

users = [1, 2, 3, 4]
admins = [5, 6, 7]

members = users + admins

puts members
# 1 2 3 4 5 6 7

subtracting

users = [1,2,3,4]
admins = [1,3]
memebrs = users - admins
puts members
# 2,4

boolean

and

users = [1,2,3,4]
admins = [1,3,5]
memebrs = users & admins
puts members
# 1,3

or

users = [1,2,3,4]
admins = [1,3,5]
memebrs = users | admins
puts members
# 1 2 3 4 5

source

ruby