Tafuta Taa ya JavaScript

Inaonyesha method ya JavaScript ya kutafuta stringi:

  • String.indexOf()
  • String.lastIndexOf()
  • String.startsWith()
  • String.endsWith()

String.indexOf()

indexOf() Methodu inaonyesha upelewa wa matukio kwenye stringiKwanzaInaonyesha (nafasi) ya upelewa:

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.indexOf("locate")    // kuwaachia 7

Try it yourself

JavaScript kinaanza na nafasi ya nimea

0 niweko wa nafasi ya kwanza ya string, 1 ni pili, 2 ni tatu ...

String.lastIndexOf()

lastIndexOf() Method inatuma indani ya kipatikana cha thamani kwenye stringi kwa mara ya kwanza.

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.lastIndexOf("locate")    // Inatuma 21

Try it yourself

Kama thamani haikupatikana:indexOf() Na lastIndexOf() Wana indani ya -1:

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.lastIndexOf("Bill")    // Inatuma -1

Try it yourself

Hizi ziko zinaingia kiwango cha kuanzia kama thamani ya pili.

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.indexOf("locate", 15)    // Inatuma 21

Try it yourself

lastIndexOf() Method inafikia kwenye mababu (kwenye mababu), maana ni: kama thamani ya pili ni 15Kama hiki, inafikia kuanzia indani ya 15 hadi kuzingia kwenye stringi.

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.lastIndexOf("locate", 15)    // Inatuma 7

Try it yourself

String.search()

search() Method inatafuta thamani kwenye stringi na inatuma indani ya kipatikana.

Mivuno

let str = "Tafuta mahali ambao "locate" inapatikana!";
str.search("locate")     // Inatuma 7

Try it yourself

Unavyopata hii?

indexOf() Na search() Hizi ziko zimeenea, ni hata hivyo?

Wana kipakana kwa vifaa, na inatuma thamani zaidi?

Hizi ziko zimeenea. Muungano wao ni:

  • search() Method haingependa kushiriki kiwango cha kuanzia kwa uangalifu wa kwanza.
  • indexOf() Method haingependa kivinjari cha uangalifu wa kirekeshi (kirekeshi).

Unatutafuta maadili ya kirekeshi kwa mafunzo ya mababu.

String.match()

Method ya match() inatafuta kipengele kwenye stringi kwa kirekeshi na inatuma kipengele kama kipengele cha Array.

Mfano 1

Tafuta "ain" kwenye stringi:

let text = "Raine in SPAIN inahitaji kwa eneo la asili";
text.match(/ain/g)    // Inatuma makorokoto [ain,ain,ain]

Try it yourself

Tafuta maadili ya kirekeshi kwa mafunzo ya JS RegExp.

Kama moja wa kirekeshi hana jina la maelezo g (kutafuta kwa jumla), method ya match() inakubali kipengele cha kwanza cha kirekeshi kwenye stringi.

Majadiliano

string.match(regexp)
regexp Inayohitajika. Kivinjari cha utafutaji, ni moja wa misingi wa kirekeshi.
Inapatikana: Makorokoto, inahusiana na kipengele, kila kipengele kinahusiana na kiwango kila moja, kama haikupatikana kipengele, inaonekana kama null.

Mfano 2

Tafuta kwa "ain" kwa uangalifu wa ukuu na ukisikia kwa jumla:

let text = "Raine in SPAIN inahitaji kwa eneo la asili";
text.match(/ain/gi)   // Inapatikana masomo [ain,AIN,ain,ain]}}

Try it yourself

String.includes()

Kama neno limechukua thamani iliyotakayishwaincludes() Methodu inapata true.

Mivuno

let text = "Hello world, welcome to the universe.";
text.includes("world")    // Inapatikana true

Try it yourself

Mwongozo wa wasafiri

Internet Explorer haikufadhaiki String.includes().

Chrome IE Firefox Safari Opera
Chrome 41 Edge 12 Firefox 40 Safari 9 Opera 28
2015 waka 3 2015 waka 7 2015 waka 8 2015 waka 10 2015 waka 3

Majadiliano

string.includes(searchvalue, start)
searchvalue Injili. Kienyeji inayotafutwa.
start Inafaa. Upo kwa kina. Mahali wa kuanza kutafuta.
Inapatikana: Inapatikana kama neno limechukua thamani iliyotakayishwa true，kama hawajatoa inapatikana false.
Wingu wa JS: ES6 (2015)

Tumia kwenye mawili wa "world", kutafuta kuanza kutoka kwa nafasi 12:

let text = "Hello world, welcome to the universe.";
text.includes("world", 12)    // Inapatikana false

Try it yourself

String.startsWith()

Kama neno limechukua thamani iliyotakayishwa kuanza kwenye mpaka wa kwanza startsWith() Methodu inapata true，kama hawajatoa inapatikana false:

Mivuno

let text = "Hello world, welcome to the universe.";
text.startsWith("Hello")   // Inapatikana true

Try it yourself

Majadiliano

string.startsWith(searchvalue, start)

Wertu wa Tambuliko

Tambuliko Maelezo
searchvalue Injili. Kienyeji inayotafutwa.
start Inafaa. Upo kwa kina. Mahali wa kuanza kutafuta.

Mivuno

let text = "Hello world, welcome to the universe.";
text.startsWith("world")    // Inapatikana false

let text = "Hello world, welcome to the universe.";
text.startsWith("world", 5)    // Inapatikana false

let text = "Hello world, welcome to the universe.";
text.startsWith("world", 6)    // Inapatikana true

Try it yourself

Note:startsWith() Methods are case-sensitive.

Internet Explorer does not support startsWith() Method.

Mishahara ya kwanza ya wasafiri ambao inahusishwa kote ni:

Chrome IE Firefox Safari Opera
Chrome 41 Edge 12 Firefox 17 Safari 9 Opera 28
2015 waka 3 2015 waka 7 2015 waka 8 2015 waka 10 2015 waka 3

String.endsWith()

Kama neno limechukua thamani iliyotakayishwa kufikia mpaka wa kwanza endsWith() Methodu inapata true，kama hawajatoa inapatikana false:

Mivuno

Tumia kwenye mawili wa "Gates":

var text = "Bill Gates";
text.endsWith("Gates")    // Inapatikana true

Try it yourself

Majadiliano

string.endsWith(searchvalue, length)

Wertu wa Tambuliko

Tambuliko Maelezo
searchvalue Injili. Kienyeji inayotafutwa.
length Optional. The length to be searched.

Retrieve the first 11 characters of the string ending with "world":

let text = "Hello world, welcome to the universe.";
text.endsWith("world", 11)    // Returns true

Try it yourself

Note:endsWith() Methods are case-sensitive.

Internet Explorer does not support endsWith() Method.

The first browser version to fully support this method is:

Chrome IE Firefox Safari Opera
Chrome 51 Edge 15 Firefox 54 Safari 10 Opera 38
May 2016 April 2017 June 2017 September 2016 June 2016

Complete string reference manual

For a complete reference, please visit our complete JavaScript String reference manual.

This manual includes descriptions and examples of all string properties and methods.