###3.Array ruby数组 ####3.1 Array简介 #####init empty array
[]
Array.new
#####非空数组
a = [1,2,3]
a[2] # 3
a[-2] # 2
a.last # 3
a[-1] # 3
#####向数组添加元素
a = [1,2,3]
a << "qwe"
a # [1,2,3,"qwe"]
a.push("ewq")
a # [1,2,3,"qwe","ewq"]
####3.2数组基础使用
#####转化数组
a = [1,2,3]
b = a.map {|i| i+2} #不会修改原数组a, map后返回一个新数组
a #[1,2,3]
b #[3,4,5]
#####数组元素过滤
a = [1,2,3]
b = a.select{|i| i%2==0}
a #[1,2,3]
b #[2]
#####数组元素删除
a = ["x","y","z"]
b = a.delete("x") #b的值是 "x"
a # ["y","z"]
a.delete_if{|i| i=="y"}
a #["z"]
####3.3 Iteration 迭代
for 循环
arr = ["w","m","d","y","b"]
for c in arr
puts c
end
each 循环
arr = ["w","m","d","y","b"]
arr.each do |c|
puts c
end
