javascript中数组的常用操作方法
2021年9月30日 15:00 by wst
javascript在学习VUE的过程中，各种数组的操作，整的我有点晕乎。这次下定决心，全部整理一遍，以此记录：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>数组操作</title>
</head>
<body>
<script>
// ---------外部循环-------------
var arr = [10, 20, 30, 40]
// 外部for循环迭代
for(let i=0;i<arr.length;i++){
console.log(i, arr[i])
}
// 外部for-in迭代
for(let i in arr){
console.log("new", arr[i])
}
// 外部for of循环
for(let i of arr){
console.log("of", i)
}
// ------------数组自带方法-----------
// 1. concat 联结两个或多个数组
var arr1=[1,2,3]
var arr2 = [4,5]
var arr3 = arr1.concat(arr2)
console.log(arr1, arr3)
// 2. join 用于把数组中所有元素放入一个字符串中
var arr = [2,3,4]
console.log(arr.join())
console.log(arr.join(";"))
// 3. push 向数组末尾添加一个或多个元素，并返回新的长度
var a = [2,3,4]
var b = a.push(5)
console.log("push", a,b)
// 4. pop 删除并返回素组的最后一个元素
var arr = [3,4,5]
console.log("pop", arr.pop())
console.log(arr)
// 5. shift 删除数组的第一个元素，并返回这个元素,改变原数组
var arr = [3,4,5]
console.log("shift", arr.shift())
console.log(arr)
// 6. unshfit 向数组开头添加一个或多个元素，并返回新长度,改变原数组
var arr = [3,4,5]
console.log("unshift", arr.unshift(3, 6))
console.log(arr)
// 7. slice 返回一个新数组，包含[start,end)的arr中的元素，不修改元素数组
var arr = [3,4,5,6,7,8]
console.log("slice", arr.slice(2,4))
console.log(arr)
// 8. splice 删除从index开始的零个或多个元素，并且用参数列表中声明的一个或多个值来替换哪些被删除的元素；
// 返回被删除的元素，改变原数组
var arr = [3,4,5,6,7,8]
console.log("splice", arr.splice(1, 0, 100)) //在第一个位置插入元素100
console.log("splice", arr.splice(2, 3)) //从第二个元素开始，删除3个
// 9. sort 排序, 改变原数组
var fruit = ['apple', 'banana', 'pear', 'cherry']
console.log("before", fruit)
fruit.sort()
console.log("sort:", fruit)
// 10. reverse 反转数组，改变原数组
var arr = [100, 20, 200]
console.log("reverse", arr.reverse())
// 11.indexOf 和 lastIndexOf 查找元素的位置
var arr = [12, 20, 80, 45, 80]
console.log("search", arr.indexOf(20, 0)) // 从起始位置往后找
console.log("search", arr.indexOf(50, 0))
console.log("last search", arr.lastIndexOf(80, 4)) // 从起始位置往前找
// 12. every 对数组的每一项都运行给定的函数, 如果都为true则返回true，否则返回false
var arr = [100, 200, 300]
function devid(element, index, ar){
return element > 200
}
console.log("every", arr.every(devid))
// 13. some 对数组的每一项都运行给定的函数，只要有一项为true，则返回true
function judge(element, index, ar){
return element > 1000
}
console.log("some", arr.some(judge))
// 14. filter 对数的每一项都运行给定的函数，返回结果为true的项组成的数组；
var words = ["spray", "limit", "elite", "exuberant", "destruction", "present", "happy"];
var longWords = words.filter(function(word){
return word.length > 6;
});
console.log("filter", longWords)
// 15. map 对数组的每一项都运行给定的函数，返回值组成一个新的数组
var numbers = [1,5,10,15]
var doubles = numbers.map((element,index)=>element * 2)
console.log("map", doubles)
// 16. forEach遍历数组
const items = ['item1', 'item2', 'item3']
const lengthArr = []
items.forEach((val, index, ar)=>lengthArr.push(val.length))
console.log("foreach", lengthArr)
// 17. reduce，对数组元素进行计算,这里为累加
s = arr.reduce((s,e)=>s+e, 0) // s 为上一次的计算结果，e为当前元素，0为计算结果的初始值
console.log("sum", s)
// es6新增的操作方法
// 18. find 查找数组中符合规则的第一个元素，并返回它
var arr = [1, "2", 3, 4, "2"]
console.log("find", arr.find(n=> (typeof n) === 'number'))
// 19. findIndex 查找数组中符合规则的第一个元素，返回它的下标
var arr = [1, "2", 3, 4, "2"]
console.log("findIndex", arr.findIndex(n=> (typeof n) === 'number'))
// 20. 查找元素（附加示例，如报错，可删除）
let data = [
{name:'张三', key:0},
{name:'李四', key:1},
{name:'王五', key:2},
{name:'老六', key:3}
]
// 目标对象的key
let key = 2
const target = data.find(item => item.key === key);
console.log(target)//{name:'王五', key:2}
// 21. 查找元素的下标
let data = [
{name:'张三', key:0},
{name:'李四', key:1},
{name:'王五', key:2},
{name:'老六', key:3}
]
// 目标对象的key
let key = 2
const target = data.findIndex(item => item.key === key);
console.log(target)//2
</script>
</body>
</html>
运行方法：把此内容粘贴到一个html文件中，并使用浏览器打开即可。
如有问题，欢迎探讨！
Comments(126) Add Your Comment
Docidk
buy generic lipitor 40mg <a href="https://lipiws.top/">purchase atorvastatin for sale</a> buy atorvastatin 10mg for sale
Bcclvp
cheap baycip - <a href="https://metroagyl.top/keflexcapsule/">keflex 250mg canada</a> amoxiclav for sale online
Udnrce
buy baycip cheap - <a href="https://cipropro.top/augmentin500/">purchase amoxiclav</a> amoxiclav pill
Rhbicr
order metronidazole 200mg generic - <a href="https://metroagyl.top/cefaclor/">buy cefaclor medication</a> buy zithromax 250mg online
Hiubkg
buy ciplox no prescription - <a href="https:/septrim.top/">ciprofloxacin 500 mg canada</a> buy erythromycin 500mg without prescription
Rlsxqv
order valacyclovir online cheap - <a href="https://gnantiviralp.com/vermox/">purchase mebendazole</a> acyclovir 800mg price
Esqheu
stromectol oral - <a href="https://keflexin.top/aczone/">order aczone for sale</a> sumycin 250mg drug
Hhhlzg
flagyl cost - <a href="https://metroagyl.top/keflexcapsule/">order amoxicillin generic</a> azithromycin sale
Zgstgk
buy ampicillin <a href="https://ampiacil.top/">buy cheap generic acillin</a> buy amoxil online
Szprjg
furosemide cost - <a href="https://antipathogenc.com/">buy furosemide tablets</a> brand capoten
Pognnl
glucophage 1000mg pill - <a href="https://gnantiacidity.com/duricef/">duricef without prescription</a> buy lincocin 500mg pill
Lwmbfx
buy generic retrovir - <a href="https://canadiangnp.com/allopurinol/">allopurinol 100mg sale</a> buy cheap generic allopurinol
Djyngc
clozapine 100mg us - <a href="https://genonlinep.com/altace/">buy generic ramipril online</a> pepcid 20mg brand
Horzdu
generic seroquel 50mg - <a href="https://gnkantdepres.com/desyrel/">buy desyrel 100mg online</a> eskalith canada
Mfncfu
order anafranil generic - <a href="https://antdeponline.com/tofranil/">order tofranil 75mg</a> doxepin order
Rhrakg
atarax oral - <a href="https://antdepls.com/">atarax pills</a> endep order online
Srlrvn
buy amoxil generic - <a href="https://atbioxotc.com/ceftin/">ceftin 500mg canada</a> order cipro 500mg without prescription
Jmiynt
buy augmentin cheap - <a href="https://atbioinfo.com/ethambutol/">ethambutol 600mg ca</a> ciprofloxacin 1000mg price
Eqhqyh
buy generic clindamycin - <a href="https://cadbiot.com/doxycycline/">buy doxycycline medication</a> buy generic chloramphenicol online
Qtynwk
buy zithromax 500mg without prescription - <a href="https://gncatbp.com/aciprofloxacin/">buy ciprofloxacin for sale</a> purchase ciprofloxacin for sale
Walumb
ivermectin 6mg tablets - <a href="https://antibpl.com/">ivermectin 3 mg</a> buy cheap cefaclor
Inqthc
albuterol price - <a href="https://antxallergic.com/xsseroflo/">buy generic seroflo for sale</a> theo-24 Cr 400 mg drug
Obqeqn
buy clarinex sale - <a href="https://rxtallerg.com/getaristocort/">order aristocort 4mg online</a> albuterol over the counter
Hsglwa
medrol cost in usa - <a href="https://ntallegpl.com/getcetirizine/">where to buy zyrtec without a prescription</a> order astelin online
Brvdvb
glyburide over the counter - <a href="https://prodeprpl.com/glipizide10/">buy glucotrol 5mg for sale</a> cost dapagliflozin 10mg
Webibg
buy prandin generic - <a href="https://depressinfo.com/">order prandin 2mg for sale</a> empagliflozin 25mg canada
Gxydwk
order metformin 1000mg generic - <a href="https://arxdepress.com/acarbose50/">precose sale</a> order acarbose 25mg without prescription
Bltbjl
order lamisil 250mg pill - <a href="https://treatfungusx.com/adiflucanv/">forcan where to buy</a> order generic grifulvin v
Ajbztb
generic semaglutide 14mg - <a href="https://infodeppl.com/glucovance5/">glucovance generic</a> buy desmopressin generic
Bqeolv
how to get ketoconazole without a prescription - <a href="https://antifungusrp.com/itraconazole100/">order sporanox 100 mg for sale</a> sporanox generic
Yvndjc
order famciclovir without prescription - <a href="https://amvinherpes.com/">purchase famvir</a> valcivir 1000mg pill
Iufyho
purchase lanoxin - <a href="https://blpressureok.com/isoptinpillmg/">calan 240mg sale</a> brand furosemide
Zaafhb
buy hydrochlorothiazide sale - <a href="https://norvapril.com/bisoprolol/">pill bisoprolol 10mg</a> bisoprolol 5mg uk
Dufbjl
buy cheap generic metoprolol - <a href="https://bloodpresspl.com/telmisartan/">buy micardis 20mg</a> nifedipine 10mg drug
Gxjtju
order nitroglycerin online - <a href="https://nitroproxl.com/valsartan/">cost diovan 80mg</a> buy diovan 80mg online
Zfjfde
rosuvastatin online balance - <a href="https://antcholesterol.com/pravastatin/">pravastatin buy purpose</a> caduet surround
Vyafuk
simvastatin halt - <a href="https://canescholest.com/gemfibrozil/">lopid furniture</a> lipitor include
Hnestl
viagra professional well - <a href="https://edsildps.com/malegra/">malegra eleven</a> levitra oral jelly sail
Wbjbkh
dapoxetine apprehension - <a href="https://promedprili.com/">dapoxetine agree</a> cialis with dapoxetine bundle
Czcfnl
cenforce online soar - <a href="https://xcenforcem.com/brandviagrasildenafil/">brand viagra online structure</a> brand viagra online unit
Xlizzd
brand cialis natural - <a href="https://probrandtad.com/viagrasofttabs/">viagra soft tabs air</a> penisole snore
Kvykkf
cialis soft tabs bitter - <a href="https://supervalip.com/cialissuperactive/">cialis super active pills school</a>1 viagra oral jelly online sore
Omynjs
brand cialis asleep - <a href="https://probrandtad.com/penisole/">penisole wave</a> penisole happy
Xzqmzc
cialis soft tabs attic - <a href="https://supervalip.com/viagrasuperactive/">viagra super active online fix</a> viagra oral jelly online frighten
Xjehvj
cenforce online stab - <a href="https://xcenforcem.com/levitraprofessional/">levitra professional staff</a> brand viagra online goblin
Rxpiee
acne medication scatter - <a href="https://placnemedx.com/">acne medication slide</a> acne medication gigantic
Gklohs
inhalers for asthma account - <a href="https://bsasthmaps.com/">inhalers for asthma base</a> asthma treatment treat
Cqxwus
uti antibiotics pleasure - <a href="https://amenahealthp.com/">uti medication melt</a> uti antibiotics slow
Dtcnei
prostatitis medications labour - <a href="https://xprosttreat.com/">prostatitis medications plastic</a> prostatitis medications charles
Qbiuvj
valtrex or - <a href="https://gnantiviralp.com/">valtrex pills master</a> valtrex pills virtue
Bufoqj
loratadine anyway - <a href="https://clatadine.top/">loratadine spread</a> claritin pills round
Rolkxy
loratadine unit - <a href="https://clatadine.top/">claritin pills wit</a> claritin pills well
Xftsxg
priligy uniform - <a href="https://prilixgn.top/">dapoxetine after</a> priligy mouse
Dtgtmh
promethazine tumble - <a href="https://prohnrg.com/">promethazine drift</a> promethazine use
Ryyokt
ascorbic acid regard - <a href="https://ascxacid.com/">ascorbic acid stranger</a> ascorbic acid delightful
Hurpov
clarithromycin pills clean - <a href="https://gastropls.com/gncytotec/">cytotec earth</a> cytotec pills feather
Fpeayi
fludrocortisone walk - <a href="https://gastroplusp.com/prlansoprazole/">prevacid venture</a> prevacid pills accident
Lviphv
buy generic dulcolax - <a href="https://gastroinfop.com/">bisacodyl online buy</a> buy liv52 20mg online
Uimuxp
aciphex 20mg for sale - <a href="https://gastrointesl.com/domperidone/">purchase domperidone pills</a> domperidone 10mg for sale
Gkvdko
bactrim 480mg uk - <a href="https://cotrioxazo.com/">brand cotrimoxazole</a> cost tobra 10mg
Qejvdf
order hydroquinone sale - <a href="https://cerazestrel.com/">desogestrel 0.075 mg drug</a> brand dydrogesterone
Quvgqh
buy forxiga 10 mg online cheap - <a href="https://forpaglif.com/">dapagliflozin online order</a> order acarbose 25mg sale
Wafrvd
buy fulvicin 250mg generic - <a href="https://gemfilopi.com/">lopid order online</a> order gemfibrozil 300mg sale
Ctpvxy
order vasotec 5mg generic - <a href="https://doxapisin.com/">buy generic doxazosin</a> latanoprost uk
Puojij
order dramamine online cheap - <a href="https://prasilx.com/">buy prasugrel 10mg pill</a> order risedronate for sale
Rydhqd
order etodolac 600mg online cheap - <a href="https://etodograph.com/">order etodolac 600mg generic</a> order cilostazol 100 mg pills
Sbanri
buy feldene online - <a href="https://feldexicam.com/">feldene 20mg cost</a> rivastigmine 3mg over the counter
Otssyn
order piracetam 800 mg generic - <a href="https://nootquin.com/praziquantel/">biltricide 600 mg pill</a> oral sinemet 20mg
Uccjhc
hydroxyurea pills - <a href="https://hydroydrinfo.com/disulfiram/">generic disulfiram 500mg</a> robaxin 500mg for sale
Zxhett
order generic depakote - <a href="https://adepamox.com/mefloquine/">buy mefloquine generic</a> buy generic topamax 100mg
Gwkswo
disopyramide phosphate us - <a href="https://anorpica.com/">disopyramide phosphate where to buy</a> order thorazine 50 mg generic
Wgrshi
cyclophosphamide ca - <a href="https://cycloxalp.com/atomoxetine/">buy atomoxetine pill</a> cost vastarel
Wgxucb
order spironolactone 100mg sale - <a href="https://aldantinep.com/">order aldactone pills</a> buy revia 50 mg without prescription
Qspnuo
brand cyclobenzaprine 15mg - <a href="https://abflequine.com/">flexeril 15mg usa</a> purchase vasotec sale
Wtinnp
order zofran for sale - <a href="https://azofarininfo.com/selegiline/">selegiline buy online</a> order requip 1mg sale
Xmqima
buy ascorbic acid paypal - <a href="https://mdacidinfo.com/ciprofloxacin/">buy ciprofloxacin generic</a> oral compro
Pvqwxp
durex gel where to buy - <a href="https://xalaplinfo.com/latanoprosteyedrops/">buy generic latanoprost online</a> buy zovirax without a prescription
Tjsuou
minoxidil without prescription - <a href="https://hairlossmedinfo.com/finasteridehl/">buy finasteride 1mg pills</a> finasteride 1mg usa
Fofpjo
buy arava 10mg online - <a href="https://infohealthybones.com/">order arava 10mg online</a> cartidin oral
Pttfpb
tenormin 50mg oral - <a href="https://heartmedinfox.com/">buy generic tenormin 50mg</a> order coreg for sale
Tbnzbc
verapamil ca - <a href="https://infoheartdisea.com/">buy verapamil without a prescription</a> tenoretic for sale
Mxtmgd
buy cheap generic atorvastatin - <a href="https://infoxheartmed.com/enalapril/">cost vasotec 10mg</a> bystolic 5mg over the counter
Etgpmn
cheap gasex pill - <a href="https://herbalinfomez.com/ashwagandha/">order ashwagandha</a> diabecon order
Cuomqe
buy noroxin cheap - <a href="https://gmenshth.com/flutamide/">cheap flutamide online</a> cheap generic confido
Owjxxq
speman price - <a href="https://spmensht.com/">speman drug</a> cheap fincar pills
Giwvrq
finasteride buy online - <a href="https://finmenura.com/doxazosin/">buy doxazosin pills</a> order uroxatral 10mg
Qwfmlc
hytrin generic - <a href="https://hymenmax.com/tamsulosin/">tamsulosin 0.4mg pill</a> priligy 30mg pill
Eantwh
oxcarbazepine tablet - <a href="https://trileoxine.com/levothyroxine/">buy generic levothyroxine</a> purchase levothyroxine pill
Ekqxhl
order cyclosporine sale - <a href="https://asimusxate.com/gloperba/">gloperba oral</a> order colchicine 0.5mg pill
Aupuas
order duphalac bottles - <a href="https://duphalinfo.com/mentat/">cheap brahmi</a> buy betahistine 16 mg pill
Sonbjc
order deflazacort generic - <a href="https://lazacort.com/brimonidine/">brand alphagan</a> order brimonidine for sale
Sucpsc
besifloxacin price - <a href="https://besifxcist.com/sildamax/">order sildamax pill</a> purchase sildamax generic
Djzile
buy benemid generic - <a href="https://bendoltol.com/">benemid uk</a> oral tegretol 200mg
Mmeudg
buy gabapentin without a prescription - <a href="https://aneutrin.com/sulfasalazine/">cheap sulfasalazine 500mg</a> order sulfasalazine pill
Shypsz
oral mebeverine - <a href="https://coloxia.com/">order mebeverine 135mg without prescription</a> order generic cilostazol 100mg
Faostm
purchase celebrex online cheap - <a href="https://celespas.com/">buy celebrex medication</a> indomethacin 75mg oral
Oorvcf
buy rumalaya pills - <a href="https://rumaxtol.com/shallaki/">shallaki generic</a> cheap elavil 10mg
Quuuld
voltaren ca - <a href="https://dicloltarin.com/aspirin/">buy aspirin 75mg generic</a> cheap aspirin 75mg
Dkbpun
cost diclofenac - <a href="https://vovetosa.com/tisosorbide/">imdur for sale</a> order nimodipine generic
Qzciwj
order pyridostigmine 60mg without prescription - <a href="https://mestonsx.com/azathioprine/">buy imuran 50mg pills</a> cost imuran
Bnfraf
buy meloxicam 7.5mg - <a href="https://meloxiptan.com/">oral meloxicam</a> ketorolac cheap
Nykdst
buy baclofen cheap - <a href="https://baclion.com/">buy generic lioresal</a> piroxicam 20 mg tablet
Yzjmtj
cyproheptadine 4mg brand - <a href="https://periheptadn.com/">cyproheptadine 4mg tablet</a> tizanidine 2mg for sale
Chdjbm
artane brand - <a href="https://voltapll.com/diclofenacgel/">order voltaren gel</a> where can i buy emulgel
Ivnkmi
isotretinoin price - <a href="https://aisotane.com/asdeltasone/">deltasone for sale online</a> buy deltasone 5mg generic
Ofnnsi
omnicef order online - <a href="https://omnixcin.com/aminocycline/"></a> buy cleocin cheap
Pdkhll
buy permethrin cream - <a href="https://actizacs.com/">order permethrin cream</a> retin usa
Fbspby
deltasone usa - <a href="https://apreplson.com/prednisolone/">buy omnacortil 20mg</a> cheap zovirax
Cmjkuy
metronidazole medication - <a href="https://cenforcevs.com/">oral cenforce</a> cenforce 100mg over the counter
Xtfuib
betamethasone online - <a href="https://betnoson.com/">betnovate cream</a> benoquin cheap
Edtzqm
augmentin 375mg uk - <a href="https://baugipro.com/">buy amoxiclav online</a> cheap synthroid online
Ujttzy
order cleocin 150mg - <a href="https://clinycinpl.com/">buy clindamycin generic</a> buy indomethacin online
Fetxzk
purchase eurax cream - <a href="https://aeuracream.com/">buy crotamiton online</a> purchase aczone online
Zihfel
order losartan 50mg sale - <a href="https://cozartan.com/">buy losartan for sale</a> keflex tablet
Dwrwck
bupropion 150mg ca - <a href="https://bupropsl.com/">order zyban 150 mg</a> buy shuddha guggulu online
Eoynfc
provigil 100mg usa - <a href="https://sleepagil.com/phenergan/">promethazine for sale</a> melatonin 3mg cheap
Zurtqt
order progesterone 100mg - <a href="https://apromid.com/">prometrium buy online</a> buy clomiphene generic
Dflmbi
purchase xeloda generic - <a href="https://xelocap.com/naproxen/">order generic naprosyn 250mg</a> cheap danazol 100mg
Gppcoq
order norethindrone 5 mg for sale - <a href="https://norethgep.com/yasmin/">yasmin online buy</a> buy yasmin without a prescription
Gflwuy
buy alendronate 35mg without prescription - <a href="https://pilaxmax.com/medroxyprogesterone/">medroxyprogesterone 5mg oral</a> order provera 5mg pills
Juyhaf
order cabergoline generic - <a href="https://adostilin.com/cabgolin/">buy cheap generic cabgolin</a> purchase alesse for sale
Siavhm
order generic yasmin - <a href="https://festrolp.com/anastrozole/">cheap anastrozole</a> anastrozole 1mg pill
Izhoqo
バイアグラ通販で買えますか - <a href="https://jpedpharm.com/">バイアグラ通販 安全</a> タダラフィル通販おすすめ
Pavdrr
гѓ—гѓ¬гѓ‰гѓ‹гѓі гЃ®иіје…Ґ - <a href="https://jpaonlinep.com/jazithromycin/">г‚ёг‚№гѓгѓћгѓѓг‚Ї жµ·е¤–йЂљиІ©</a> г‚ёг‚№гѓгѓћгѓѓг‚ЇйЂљиІ©гЃ§иІ·гЃ€гЃѕгЃ™гЃ‹
Hxerck
eriacta bill - <a href="https://eriagra.com/dapcalisb/">apcalis shrill</a> forzest copy