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Ruby笔记四(数组) - #E8.1-1.rb
- =begin
- 数组的索引从0开始,一直到数组的长度减去1;
- 负数表示从数组末尾开始的索引;
- 用一对数字来索引数组,第一个数字表示开始位置,第二数字表示从开始位置起的元素数目
- =end
- arr=[3,4,5,6,7,8,9]
- puts arr[0] #3
- puts arr.first #3
- puts arr[arr.length-1] #9
- puts arr[arr.size-1] #9
- puts arr.last #9
- puts arr[-1] #9
- puts arr[-2] #8
- print arr[1..3].join(",") ,"\n" #4, 5, 6
- print arr[-3,2] ,"\n" #[7, 8]
- #Ruby的数组大小是动态的,你能够随时增加、删除数组元素。
- arr=[4,5,6]
- print arr.join(", "),"\n" #4, 5, 6
- arr[4] = "m" #把4号索引位置元素赋值为"m"
- print arr.join(", "),"\n" #4, 5, 6, , m
- print arr[3] ,"\n" #打印3号索引位置元素 #nil
- arr.delete_at(3) #删除3号索引位置元素
- print arr.join(", "),"\n" #4, 5, 6, m
- arr[2] = ["a","b","c"] #把2号索引位置元素赋值为["a","b","c"]
- print arr.join(", "),"\n" #4, 5, a, b, c, m
- print arr[2].join(",") ,"\n" #打印2号索引位置元素 #a,b,c
- arr[0..1] = [7,"h","b"] #把0..1号元素替换为7,"h","b"
- print arr.join(", "),"\n" #7, h, b, a, b, c, m
- arr.push("b" ) #加入元素"b"
- print arr.join(", "),"\n" #7, h, b, a, b, c, m, b
- arr.delete(["a","b","c"] ) #删除元素["a","b","c"]
- print arr.join(", "),"\n" #7, h, b, m, b
- arr.delete("b") #删除所有元素"b"
- print arr.join(", "),"\n" #7, h, m
- arr.insert(3,"d") #在3号索引位置插入元素"d"
- print arr.join(", "),"\n" #7, h, m, d
- arr<<"f"<<2 #加入元素"f";加入元素2
- print arr.join(", "),"\n" #7, h, m, d, f, 2
- arr.pop #删除尾元素
- print arr.join(", "),"\n" #7, h, m, d, f
- arr.shift #删除首元素
- print arr.join(", "),"\n" #h, m, d, f
- arr.clear #清空数组arr
- print arr.join(", "),"\n" #
- #数组运算
- aaaa=["aa",4,5,"bb"]
- bbbb=[4,1,3,2,5]
- print (aaaa + bbbb).join(" ") ,"\n" #aa 4 5 bb 4 1 3 2 5
- print (aaaa * 2).join(" ") ,"\n" #aa 4 5 bb aa 4 5 bb
- print (bbbb - aaaa).join(" ") ,"\n" #1 3 2
- #并运算;交运算
- print (aaaa | bbbb).join(",") ,"\n" #aa,4,5,bb,1,3,2
- print (aaaa & bbbb).join(",") ,"\n" #4,5
- #排序;倒置
- print bbbb.sort().join(",") ,"\n" #1,2,3,4,5
- print aaaa.reverse.join(",") ,"\n" #bb,5,4,aa
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