Fungsi iki dirancang khusus kanggo mriksa apa string 'ngemot' string liyane utawa ora. Yen sampeyan anyar babagan iki, sampeyan bisa uga nggunakake aplikasi kasebut kanggo nemokake 'karakter'. Nanging ora bakal migunani. Ing artikel iki, kita bakal alamat carane java.lang.String.contains () digunakake, dipun ginakaken lan apa pangecualian bisa njedhul yen ora digunakake kasebut kanthi teliti,.
Apa metode ngandhut ()?
Sampeyan bisa nggunakake cara ngemot (String key) kanggo " golek " yen string tartamtu " kunci " ana ing string tartamtu utawa ora. Yen "kunci" ditemokake, "bener" bali. Yen ora, sampeyan bakal entuk "palsu".
Implementasi Internal
Cara iki wis dileksanakake dening java.lang.String . Sampeyan ora kudu ngetrapake iki dhewe. Mangkene panjelasan cepet babagan iki kanggo pangerten sampeyan.
public class ContainsMethod
{
public boolean contains(CharSequence key)
{
return indexOf(key.toString()) > -1;
}
}
Katrangan Kode
ngandhut () cara, njupuk CharSequence minangka parameter input. Sing mengko diowahi dadi "String". Banjur ekspresi iki diitung indexOf(key.toString()) > -1; . Tegese, yen "kunci" kasebut ditemokake ing indeks apa wae ("0" utawa luwih gedhe) banjur "bener" bali. Lan yen kunci ora ditemokake, banjur "palsu" bali.
Kepiye cara nggunakake metode ngemot ()?
Mangkene carane sampeyan bisa nggunakake.
public class ContainsMethod {
public static void main(String[] args) {
String input = "A brown fox jumped over a lazy dog.";
// check the containing strings
System.out.println("input.contains(bro) = " + input.contains("bro"));
System.out.println("input.contains(brown) = " + input.contains("brown"));
System.out.println("input.contains(Brown) = " + input.contains("Brown"));
System.out.println("input.contains(fox) = " + input.contains("fox"));
System.out.println("input.contains(xof) = " + input.contains("xof"));
System.out.println("input.contains(dog) = " + input.contains("dog"));
System.out.println("input.contains(lazyy) = " + input.contains("lazyy"));
System.out.println("input.contains(jumping) = " + input.contains("jumping"));
}
}
Output
input.contains(bro) = true input.contains(brown) = true input.contains(Brown) = false // false because case-sensitive input.contains(fox) = true input.contains(xof) = false // palsu amarga urutane kudu padha input.contains(asu) = true input.contains(lazyy) = false // false because whole substring not found input.contains(jumping) = false
Katrangan Kode
Wigati dimangerteni, cara iki sensitif huruf cilik kanggo parameter input. Dadi ing cuplikan ing ndhuwur, sampeyan bisa mirsani nalika sampeyan nggoleki "coklat" bener bali, dene palsu bali kanggo "Coklat". Uga, sampeyan bakal bener yen sampeyan nemokake "rubah" lan palsu kanggo "xof" utawa "oxf" amarga urutan karakter kudu padha. Pungkasan, yen sampeyan nemokake "mlumpat" utawa "mlumpat" sampeyan bakal entuk bener amarga kabeh parameter ana ing string " input ". Dene, yen sampeyan mriksa "mlumpat" palsu bali amarga kabeh tombol ("mlumpat") ora ditemokake.
Ngurusi Pengecualian
java.lang.String.contains () cara asil ing Null Pointer Exception yen lali kanggo initialize senar parameter karo sawetara Nilai konkrit.
public class ContainsMethod {
public static void main(String[] args) {
String input = "Here is a test string.";
String test = null;
// check what happens if you look for a null string
System.out.println("input.contains(test) = " + input.contains(test));
}
}
Output
Exception in thread "main" java.lang.NullPointerException
at java.lang.String.contains(String.java:2133)
at ContainsMethod.main(ContainsMethod.java:8)
Kesimpulan
Contains () cara nyedhiyakake sarana java sing praktis kanggo nemokake urutan char utawa string. Muga-muga ing pungkasan kiriman iki, sampeyan wis ngerti panggunaan lan implementasine. Kanggo pangerten sing luwih apik, sampeyan disaranake nggulung lengen klambi lan kerja. Nggawe kode kesalahan-free nerangake karo gaweyan konsisten. Dadi ayo padha njaluk! Sampeyan mesthi seneng bali ing kene yen sampeyan lagi macet. Sugeng Coding. :)
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