Rubyの配列は、変数、数字、いろいろ混ぜ込みOK
friends = Array[1,"karen","Oscar"]
friends = Array["Kevin","karen","Oscar"]
puts friends[0]
"Kevin"
puts friends[-1]
"Oscar"
puts friends[-2]
"Karen"
puts friends[0,2]
"Kevin"
"Karen"
puts friends[0,3]
"Kevin"
"Karen"
"Oscar"
friends = Array["Kevin","karen","Oscar"]
friends[0] = "Dwight"
puts friends[0]
Dwight
friends = Array.new
friends[0] 0 "Michael"
friends[5] = "Holly"
puts friends
"Michael"
"Holly"
friends = Array["Kevin", "karen", "Oscar"]
puts friends.length()
3
puts friends.include? "Karen"
True
puts friends.include? "Karens"
False
puts friends.reverse()
Oscar
Karen
Kevin
friends = Array["Kevin", "karen", "Oscar","Andy"]
puts friends.sort()
Andy
Karen
Kevin
Oscar
friends = Array["Kevin", 1, "Oscar","Andy"]
puts friends.sort()
error （型が違うからソートできない）