Module: collection

//{true: 5, false: 4}console.log(_.countBy([1,'a',3,'b',5,'c',7,'d',9],_.isNumber))const users = [ {name:'zhangsan',sex:'m',age:33}, {name:'lisi',sex:'f',age:21}, {name:'wangwu',sex:'m',age:25}, {name:'zhaoliu',sex:'m',age:44},]//{m: 3, f: 1} 性别分布统计console.log(_.countBy(users,u=>u.sex))//{20: 2, 30: 1, 40: 1} 年龄段分布统计console.log(_.countBy(users,u=>(u.age/10>>0)*10))

//1、2、3_.each(new Set([1,2,3]),console.log)//a、b、c_.each({'1':'a','2':'b','3':'c'},console.log)//1、{"a":1}、[2,3]_.each([1,{a:1},[2,3]],console.log)//h/o/l/y/h/i/g/h_.each('holyhigh',console.log)//遍历元素集合const x=[];_.each(document.body.children,v=>x.push(v));console.log(x)

//3、2、1_.eachRight(new Set([1,2,3]),console.log)//c、b、a_.eachRight({'1':'a','2':'b','3':'c'},console.log)//[2,3]、{"a":1}、1_.eachRight([1,{a:1},[2,3]],console.log)//hgihyloh_.eachRight('holyhigh',console.log)

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:true}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:false}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//trueconsole.log(_.every([]))//trueconsole.log(_.every([1,3,5],v=>v%2===1))//falseconsole.log(_.every(['a','b','c',1],_.isNumber))//falseconsole.log(_.every(libs,'tags.utils'))//falseconsole.log(_.every(libs,{js:true}))//false key不支持路径解析console.log(_.every(libs,{'platform[0]':'web'}))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:false}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:true}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//[]console.log(_.filter())//[1,3]console.log(_.filter([1,2,3,4],v=>v%2===1))//[1]console.log(_.filter(['a','b','c',1],_.isNumber))//[1,2]console.log(_.filter({a:1,b:2,c:'3'},_.isNumber))//[f、s]console.log(_.filter(libs,'tags.utils'))//[j、s]console.log(_.filter(libs,{js:true}))//[] key不支持路径解析console.log(_.filter(libs,{'platform[0]':'web'}))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:false}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:true}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//1console.log(_.find(['a','b','c',1,3,6],_.isNumber))//holyhighconsole.log(_.find({a:1,b:true,c:'holyhigh',d:'func.js'},_.isString))//{f}console.log(_.find(libs,'tags.utils'))//{j}console.log(_.find(libs,{js:true}))//undefined key不支持路径解析console.log(_.find(libs,{'tags.utils':false}))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:false},js:false}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:true}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//6console.log(_.findLast(['a','b','c',1,3,6],_.isNumber))//func.jsconsole.log(_.findLast({a:1,b:true,c:'holyhigh',d:'func.js'},_.isString))//{s}console.log(_.findLast(libs,'tags.utils'))//{s}console.log(_.findLast(libs,{js:true}))//undefined key不支持路径解析console.log(_.findLast(libs,{'tags.utils':false}))

//[1, 2, [3]]console.log(_.flatMap([[1,2],[[3]]]))//[3,5]console.log(_.flatMap([[1,2],3,4,5],n=>n%2?n:[]))

//[1, 2, 3]console.log(_.flatMapDeep([[1,2],[[3]]]))

//{true: [1, 3, 5, 7, 9], false: ['a', 'b', 'c', 'd']}console.log(_.groupBy([1,'a',3,'b',5,'c',7,'d',9],_.isNumber))const users = [ {name:'zhangsan',sex:'m',age:33}, {name:'lisi',sex:'f',age:21}, {name:'wangwu',sex:'m',age:25}, {name:'zhaoliu',sex:'m',age:44},]//{m: [{...},{...},{...}], f: [{...}]} 性别分布统计console.log(_.groupBy(users,u=>u.sex))//{20: [{...},{...}], 30: [{...}], 40: [{...}]} 年龄段分布统计console.log(_.groupBy(users,u=>(u.age/10>>0)*10))

//trueconsole.log(_.includes({a:1,b:2},2))//falseconsole.log(_.includes([1,3,5,7,[2]],2))//trueconsole.log(_.includes([1,3,5,7,[2]],3))//falseconsole.log(_.includes([1,3,5,7,[2]],3,2))//trueconsole.log(_.includes([0,null,undefined,NaN],NaN))//trueconsole.log(_.includes('abcdefg','abc'))//falseconsole.log(_.includes('abcdefg','abc',2))//falseconsole.log(_.includes('aBcDeFg','abc'))

//{true: 9, false: 'd'}console.log(_.keyBy([1,'a',3,'b',5,'c',7,'d',9],_.isNumber))gconst users = [ {name:'zhangsan',sex:'m',age:33}, {name:'lisi',sex:'f',age:21}, {name:'wangwu',sex:'m',age:25}, {name:'zhaoliu',sex:'m',age:44},]//{m: {...}, f: {...}}console.log(_.keyBy(users,u=>u.sex))//{20: {...}, 30: {...}, 40: {...} }console.log(_.keyBy(users,u=>(u.age/10>>0)*10))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:false}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:true}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//[2,4,6]console.log(_.map(new Set([1,2,3]),v => v*2))//[1,2,3]console.log(_.map({'1':'a','2':'b','3':'c'},(v,k)=>k))//[true,false,false]console.log(_.map([1,{a:1},[2,3]],v => _.isNumber(v)))//["H", "O", "L", "Y", "H", "I", "G", "H"]console.log(_.map('holyhigh',v => String.fromCharCode(v.charCodeAt(0)-32)))//[true,false,true]console.log(_.map(libs,'tags.utils'))//["func.js", "juth2", "soya2d"]console.log(_.map(libs,'name'))//[1,2,3]console.log(_.map({a:1,b:2,c:3}))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:false}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:true}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//[[func.js],[juth2,soya2d]]console.log(_.partition(libs,{name:'func.js'}))const seq = [1,2,3,4,5,6];//[[2, 4, 6],[1, 3, 5]]console.log(_.partition(seq,n=>n%2===0))//[[1,3],["2"]]console.log(_.partition({a:1,b:'2',c:3},_.isNumber))

//25console.log(_.reduce([1,3,5,7,9],(a,v)=>a+v))//35console.log(_.reduce([1,3,5,7,9],(a,v)=>a+v,10))//x-y-zconsole.log(_.reduce({x:1,y:2,z:3},(a,v,k)=>a+'-'+k,'').substr(1))

//['a', 'b', 'c']console.log(_.reject(['a','b','c',1],_.isNumber))//['3']console.log(_.reject({a:1,b:2,c:'3'},_.isNumber))//[2，4]console.log(_.reject([1,2,3,4],v=>v%2===1))

//随机值console.log(_.sample([1,2,3,4,5,6,7,8,9,0]))//随机值console.log(_.sample({a:1,b:2,c:3,d:4,e:5}))

//[随机值]console.log(_.sampleSize([1,2,3,4,5,6,7,8,9,0]))//[随机值1,随机值2]console.log(_.sampleSize([{a:1},{b:2},{c:3},{d:4},{e:5}],2))//[随机值1,随机值2,随机值3]console.log(_.sampleSize({a:1,b:2,c:3,d:4,e:5},3))

//[随机内容]console.log(_.shuffle([1,2,3,4,5,6,7,8,9,0]))//[随机内容]console.log(_.shuffle([{a:1},{a:2},{a:3},{a:4},{a:5}]))//[随机内容]console.log(_.shuffle({a:1,b:2,c:3,d:4,e:5}))

//3console.log(_.size({a:1,b:2,c:{x:1}}))//0console.log(_.size(null))//3console.log(_.size(new Set([1,2,3])))//2console.log(_.size([1,[2,[3]]]))//2console.log(_.size(document.body.children))//4console.log(_.size(document.body.childNodes))//3 arguments已不推荐使用，请使用Rest参数console.log((function(){return _.size(arguments)})('a',2,'b'))//7console.log(_.size('func.js'))

const libs = [ {name:'func.js',platform:['web','nodejs'],tags:{utils:true},js:true}, {name:'juth2',platform:['web','java'],tags:{utils:false,middleware:true},js:false}, {name:'soya2d',platform:['web'],tags:{utils:true},js:true}];//falseconsole.log(_.some([]))//trueconsole.log(_.some([1,2,3,4],v=>v%2===1))//trueconsole.log(_.some(['a','b','c',1],_.isNumber))//trueconsole.log(_.some(libs,'tags.middleware'))//trueconsole.log(_.some(libs,{js:true}))//false key不支持路径解析console.log(_.some(libs,{'tags.utils':false}))

//字符排序 ['lao1', 'lao2', 'lao3']console.log(_.sort(['lao1','lao3','lao2']))//数字排序[7, 9, 80]console.log(_.sort([9,80,7]))//日期排序["3/1/2019", "2020/1/1", Wed Apr 01 2020...]console.log(_.sort([new Date(2020,3,1),'2020/1/1','3/1/2019']))//第一个元素不是日期对象，需要转换console.log(_.sort(_.map(['2020/1/1',new Date(2020,3,1),'3/1/2019'],v=>new Date(v))))//对象排序const users = [ {name:'zhangsan',age:53}, {name:'lisi',age:44}, {name:'wangwu',age:25}, {name:'zhaoliu',age:36}];//[25,36,44,53]console.log(_.sort(users,(a,b)=>a.age-b.age))// 倒排console.log(_.sort(users,(a,b)=>b.age-a.age))

//不变console.log(_.sortBy([{a:2},{a:1},{a:3}]))//[{{a:1},{a:2},{a:3}] 通过iteratee把集合变为数字后排序console.log(_.sortBy([{a:2},{a:1},{a:3}],'a'))//['3/1/2019', '2020/1/1', '2020-3-1']console.log(_.sortBy(['2020-3-1','2020/1/1','3/1/2019'],_.toDate))

//[1,2,3]console.log(_.toArray(new Set([1,2,3])))//['a','b','c']console.log(_.toArray('abc'))//[1,2,'b']console.log(_.toArray({x:1,y:2,z:'b'}))//[[1, 'a'], [3, 'b'], ['a', 5]]console.log(_.toArray(new Map([[1,'a'],[3,'b'],['a',5]])))