Ruby 數組操作方法(轉)

函數名稱	說明	示例
&	數組與，返回兩數組的交集	[1,2] & [2,3] =>[2]
*	復制數組n次	[1,2]*2       => [1,2,1,2]
+	返回兩數組的並集，但不排除重復元素	[1,2]+[2,3]    =>[1,2,2,3]
<<	追加元素，但不排除重復元素	[1,2]<<[2,3]   => [1,2,2,3]
|	追加元素，但排除重復元素	[1,2] | [2,3]    => [1,2,3]
-	返回第一個數組與第二個數組不同的元素	[1,2]-[2,3]    => [1]
<=>	比較數組	[1,2]<=>[2,3] =>flase
==	比較數組，若所有元素均相等時返回真	[1,2]==[2,1]    =>flase
assoc	從數組的每個元素中尋找指定對象	[[1,2],[3,4]].assoc(2)=> [1,2]
at	找到數組的第N個元素   負數表示逆向查找	["a","b","c","d","e"].at(0) => "a"   ["a","b","c","d","e"].at(-1)  => "e"
clear	刪除數組中的所有元素	["a","b","c","d","e"]. clear
collect   collect！	用一個過程塊對數組的每個元素進行處理	["a","b","c","d"].collect {|x| x + "!" }    => ["a!", "b!", "c!", "d!"]
compact   compact!	刪除值為nil的元素后生成新數組並返回它	["a",nil,"b",nil,"c",nil].compact    => ["a", "b", "c"]
delete	刪除元素，如果元素重復，全部刪除	a = [ "a", "b", "b", "b", "c" ]    a.delete("b")   puts a    => ["a","c"]
delete_at	刪除pos所指位置的元素並返回它。若pos超出數 組范圍則返回nil	a = %w( ant bat cat dog )    a.delete_at(2)   » "cat"    a=> ["ant", "bat", "dog"]    a.delete_at(99) => nil
delete_if	根據條件刪除	a = [ "a", "b", "c" ]    a.delete_if {|x| x >= "b" } => ["a"]
each	對數組的每個元素按值進行迭代操作 查尋方法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	對數組的每個元素按索引進行迭代操作	a = [ "a", "b", "c" ]   a.each_index {|x| print x, " -- " }   => "0 -- 1 -- 2 --"
empty?	判斷數組是否為空，為空則返回真	[].empty?=> true
eql！	比較兩數組是否相等	["a","b","c"].eql?(["a","b","c"]) => true
fill	填充數組	["a","b","c","d"].fill("x")    => ["x","x","x","x"]    ["a","b","c","d"].fill("z", 2, 2)    => ["x", "x", "z", "z"]
first	返回數組的首元素。若沒有首元素則返回nil	[ "q", "r", "s", "t" ].first   => "q"
last	返回數組末尾的元素。若數組為空時，返回nil	["w","x","y","z"].last     => "z"
include?	判斷數組中是否包含元素	a = [ "a", "b", "c" ]    a.include?("b") => true    a.include?("z") => false
index	返回數組中第一個==val的元素的位置	a = [ "a", "b", "c" ]    a.index("b") => 1    a.index("z") => nil
indexes	以數組形式返回其索引值與各參數值相等的元素	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	在索引為nth的元素前面插入第2參數以后的值	ary = %w(foo bar baz)   ary.insert 2,'a','b'   p ary => ["foo", "bar", "a", "b", "baz"]
join	將數組元素按一定的分隔符連接起來	[ "a", "b", "c" ].join=> "abc"    [ "a", "b", "c" ].join("-") => "a-b-c"
length     size	返回數組長度。若數組為空則返回0	[1,2,3].length   => 3   [1,2,3].size      => 3
nitems	返回非nil元素的個數	[ 1, nil, 3, nil, 5 ].nitems => 3
pop	刪除末尾元素並返回它。若數組為空則返回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	遍歷數組每個元素（元素必須是數組），匹配索引為1的值是否與查找的字符相等，返回第一個相等的元素	a = [[15,1], [25,2], [35,2]]   p a.rassoc(2)         => [25, 2]
replace	替換數組元素	a = ["a","b"]    a.replace(["x","y","z"])     p a                 =>["x", "y", "z"]
reverse     reverse！	將所有元素以逆序重新排列生成新數組並返回它	["a","b","c" ].reverse=> ["c", "b", "a"]
rindex	返回最后一個值相等的元素的索引值	a = [ "a","b","b","b","c"]    a.rindex("b")           => 3
shift	刪除數組的首元素並返回它。剩余元素依次提前。若數組為空返回nil	args = ["-m","-q","filename"]    args.shift => "-m"    args => ["-q", "filename"]
sort     sort!	從小到大排序	a = [ "d", "a", "e", "c", "b" ]    a.sort  => ["a", "b", "c", "d", "e"]
uniq     uniq！	刪除數組中的重復元素后生成新數組並返回它	a = [ "a", "a", "b", "b", "c" ]    a.uniq    => ["a", "b", "c"]
unshift	在數組第一個元素前添加元素	a = [ "b", "c", "d" ]    a.unshift("a")  => ["a", "b", "c", "d"]
to_s	將數組的所有元素連接成字符串	["a","e","i","o"].to_s  => "aeio"