【转载】ruby 中数组函数示例（1）（转）

函数名称	说明	示例
&	数组与，返回两数组的交集	[1,2] & [2,3] =>[2]
*	复制数组n次	[1,2]*2       => [1,2,1,2]
+	返回两数组的并集，但不排除重复元素	[1,2]+[2,3]    =>[1,2,2,3]
<<	追加元素，但不排除重复元素	[1,2]<<[2,3]   => [1,2,2,3]
|	追加元素，但排除重复元素	[1,2] | [2,3]    => [1,2,3]
-	返回第一个数组与第二个数组不同的元素	[1,2]-[2,3]    => [1]
<=>	比较数组	[1,2]<=>[2,3] =>flase
==	比较数组，若所有元素均相等时返回真	[1,2]==[2,1]    =>flase
assoc	从数组的每个元素中寻找指定对象	[1,2],[3,4]].assoc(2)=> [1,2]
at	找到数组的第N个元素 负数表示逆向查找	["a","b","c","d","e"].at(0) => "a" ["a","b","c","d","e"].at(-1)  => "e"
clear	删除数组中的所有元素	["a","b","c","d","e"]. Clear
collect collect！	用一个过程块对数组的每个元素进行处理	["a","b","c","d"].collect {|x| x + "!" }  => ["a!", "b!", "c!", "d!"]
compact compact!	删除值为nil的元素后生成新数组并返回它	["a",nil,"b",nil,"c",nil].compact   => ["a", "b", "c"]
count	统计数组中某元素的个数	[1,2,3,4,1,3,1,6].count(1) =>3
delete	删除元素，如果元素重复，全部删除	a = [ "a", "b", "b", "b", "c" ]  a.delete("b") puts a    => ["a","c"]
delete_at	删除pos所指位置的元素并返回它。若pos超出数 组范围则返回nil	a = %w( ant bat cat dog )  a.delete_at(2)   ? "cat"  a=> ["ant", "bat", "dog"] a.delete_at(99) => nil
delete_if	根据条件删除	a = [ "a", "b", "c" ]  a.delete_if {|x| x >= "b" } => ["a"]
each	对数组的每个元素按值进行迭代操作 查寻方法find，也有：list = ['a','b','c']  list.find{|x| x=='c'}	a = [ "a", "b", "c" ] a.each {|x| print x, " -- " }   =>  "a -- b -- c --"
each_index	对数组的每个元素按索引进行迭代操作	a = [ "a", "b", "c" ] a.each_index {|x| print x, " -- " } => "0 -- 1 -- 2 --"
empty?	判断数组是否为空，为空则返回真	[].empty?=> true
eql！	比较两数组是否相等	["a","b","c"].eql?(["a","b","c"]) => true
fill	填充数组	["a","b","c","d"].fill("x")  => ["x","x","x","x"] ["a","b","c","d"].fill("z", 2, 2)  => ["x", "x", "z", "z"]
first	返回数组的首元素。若没有首元素则返回nil	[ "q", "r", "s", "t" ].first   => "q"
last	返回数组末尾的元素。若数组为空时，返回nil	["w","x","y","z"].last     => "z"
include?	判断数组中是否包含元素	a = [ "a", "b", "c" ]  a.include?("b") => true  a.include?("z") => false
index	返回数组中第一个==val的元素的位置	a = [ "a", "b", "c" ]  a.index("b") => 1  a.index("z") => nil
indexes	以数组形式返回其索引值与各参数值相等的元素	a = [ "a", "b", "c", "d", "e", "f", "g" ]  a.indexes(0, 2, 4)   => ["a", "c", "e"]  a.indexes( 2, 4, 12)=> [ "c", "e", nil]
insert	在索引为nth的元素前面插入第2参数以后的值	ary = %w(foo bar baz) ary.insert 2,'a','b' p ary => ["foo", "bar", "a", "b", "baz"]
join	将数组元素按一定的分隔符连接起来	[ "a", "b", "c" ].join=> "abc"  [ "a", "b", "c" ].join("-") => "a-b-c"
length size	返回数组长度。若数组为空则返回0	[1,2,3].length   => 3 [1,2,3].size      => 3
nitems	返回非nil元素的个数	[ 1, nil, 3, nil, 5 ].nitems => 3
pop	删除末尾元素并返回它。若数组为空则返回nil	a = [ "a", "m", "z" ]  a.pop             => "z"  p a                 => ["a", "m"]
push	添加新元素	["a","b"].push(['1','2']) =>["a", "b", ["1", "2"]]
rassoc	遍历数组每个元素（元素必须是数组），匹配索引为1的值是否与查找的字符相等，返回第一个相等的元素	a = [[15,1], [25,2], [35,2]] p a.rassoc(2)         => [25, 2]
replace	替换数组元素	a = ["a","b"]  a.replace(["x","y","z"])   p a                 =>["x", "y", "z"]
reverse reverse！	将所有元素以逆序重新排列生成新数组并返回它	["a","b","c" ].reverse=> ["c", "b", "a"]
rindex	返回最后一个值相等的元素的索引值	a = [ "a","b","b","b","c"]  a.rindex("b")           => 3
shift	删除数组的首元素并返回它。剩余元素依次提前。若数组为空返回nil	args = ["-m","-q","filename"]  args.shift => "-m"  args => ["-q", "filename"]
sort sort!	从小到大排序	a = [ "d", "a", "e", "c", "b" ]  a.sort  => ["a", "b", "c", "d", "e"]
uniq uniq！	删除数组中的重复元素后生成新数组并返回它	a = [ "a", "a", "b", "b", "c" ]  a.uniq    => ["a", "b", "c"]
unshift	在数组第一个元素前添加元素	a = [ "b", "c", "d" ]  a.unshift("a")  => ["a", "b", "c", "d"]
to_s	将数组的所有元素连接成字符串	["a","e","i","o"].to_s  => "aeio"