【转载】ruby 中数组函数示例(1)(转)
2024-08-28 23:10:54
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) |
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" |
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