Java: método para obtener la posición de una coincidencia en una cadena?
String match = "hello";
String text = "0123456789hello0123456789";
int position = getPosition(match, text); // should be 10, is there such a method?
13 answers
La familia de métodos que hace esto son:
Devuelve el índice dentro de esta cadena de la primera ( o última) ocurrencia de la subcadena especificada [buscando hacia adelante ( o hacia atrás) a partir del índice especificado].
String text = "0123hello9012hello8901hello7890";
String word = "hello";
System.out.println(text.indexOf(word)); // prints "4"
System.out.println(text.lastIndexOf(word)); // prints "22"
// find all occurrences forward
for (int i = -1; (i = text.indexOf(word, i + 1)) != -1; i++) {
System.out.println(i);
} // prints "4", "13", "22"
// find all occurrences backward
for (int i = text.length(); (i = text.lastIndexOf(word, i - 1)) != -1; i++) {
System.out.println(i);
} // prints "22", "13", "4"
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2017-07-20 02:53:06
Esto funciona usando expresiones regulares.
String text = "I love you so much";
String wordToFind = "love";
Pattern word = Pattern.compile(wordToFind);
Matcher match = word.matcher(text);
while (match.find()) {
System.out.println("Found love at index "+ match.start() +" - "+ (match.end()-1));
}
Salida :
Encontrado 'amor' en el índice 2-5
Regla general:
- Búsqueda de expresiones regulares de izquierda a derecha, y una vez que los caracteres coincidentes se han utilizado, no se puede reutilizar.
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-02-06 16:39:38
text.indexOf(match);
Ver la cadena javadoc
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2010-04-11 01:46:01
Encontrar un único índice
Como otros han dicho, use text.indexOf(match)
para encontrar una sola coincidencia.
String text = "0123456789hello0123456789";
String match = "hello";
int position = text.indexOf(match); // position = 10
Encontrando múltiples índices
Debido al comentario de @StephenC sobre la mantenibilidad del código y mi propia dificultad para comprender la respuesta de @polygenelubricants, quería encontrar otra manera de obtener todos los índices de una coincidencia en una cadena de texto. El siguiente código (que se modifica de esta respuesta) lo hace:
String text = "0123hello9012hello8901hello7890";
String match = "hello";
int index = text.indexOf(match);
int matchLength = match.length();
while (index >= 0) { // indexOf returns -1 if no match found
System.out.println(index);
index = text.indexOf(match, index + matchLength);
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-02-06 16:31:45
Use cadena.indexOf para obtener el índice inicial.
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2010-04-11 01:45:58
Puede obtener todas las coincidencias en un archivo simplemente asignando dentro de while-loop, cool:
$ javac MatchTest.java
$ java MatchTest
1
16
31
46
$ cat MatchTest.java
import java.util.*;
import java.io.*;
public class MatchTest {
public static void main(String[] args){
String match = "hello";
String text = "hello0123456789hello0123456789hello1234567890hello3423243423232";
int i =0;
while((i=(text.indexOf(match,i)+1))>0)
System.out.println(i);
}
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2010-04-11 02:21:47
int match_position=text.indexOf(match);
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2014-03-03 10:47:08
import java.util.StringTokenizer;
public class Occourence {
public static void main(String[] args) {
String key=null,str ="my name noorus my name noorus";
int i=0,tot=0;
StringTokenizer st=new StringTokenizer(str," ");
while(st.hasMoreTokens())
{
tot=tot+1;
key = st.nextToken();
while((i=(str.indexOf(key,i)+1))>0)
{
System.out.println("position of "+key+" "+"is "+(i-1));
}
}
System.out.println("total words present in string "+tot);
}
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2014-02-09 20:54:27
Tengo un código grande pero funciona muy bien....
class strDemo
{
public static void main(String args[])
{
String s1=new String("The Ghost of The Arabean Sea");
String s2=new String ("The");
String s6=new String ("ehT");
StringBuffer s3;
StringBuffer s4=new StringBuffer(s1);
StringBuffer s5=new StringBuffer(s2);
char c1[]=new char[30];
char c2[]=new char[5];
char c3[]=new char[5];
s1.getChars(0,28,c1,0);
s2.getChars(0,3,c2,0);
s6.getChars(0,3,c3,0); s3=s4.reverse();
int pf=0,pl=0;
char c5[]=new char[30];
s3.getChars(0,28,c5,0);
for(int i=0;i<(s1.length()-s2.length());i++)
{
int j=0;
if(pf<=1)
{
while (c1[i+j]==c2[j] && j<=s2.length())
{
j++;
System.out.println(s2.length()+" "+j);
if(j>=s2.length())
{
System.out.println("first match of(The) :->"+i);
}
pf=pf+1;
}
}
}
for(int i=0;i<(s3.length()-s6.length()+1);i++)
{
int j=0;
if(pl<=1)
{
while (c5[i+j]==c3[j] && j<=s6.length())
{
j++;
System.out.println(s6.length()+" "+j);
if(j>=s6.length())
{
System.out.println((s3.length()-i-3));
pl=pl+1;
}
}
}
}
}
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2015-07-08 07:58:39
//finding a particular word any where inthe string and printing its index and occurence
class IndOc
{
public static void main(String[] args)
{
String s="this is hyderabad city and this is";
System.out.println("the given string is ");
System.out.println("----------"+s);
char ch[]=s.toCharArray();
System.out.println(" ----word is found at ");
int j=0,noc=0;
for(int i=0;i<ch.length;i++)
{
j=i;
if(ch[i]=='i' && ch[j+1]=='s')
{
System.out.println(" index "+i);
noc++;
}
}
System.out.println("----- no of occurences are "+noc);
}
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2015-09-01 07:18:56
Si vas a buscar' n ' coincidencias de la cadena de búsqueda, te recomiendo usar expresiones regulares. Tienen una curva de aprendizaje empinada, pero te ahorrarán horas cuando se trata de búsquedas complejas.
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2015-06-22 14:26:55
Para ocurrencia múltiple y el carácter encontrado en cadena??sí o no
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class SubStringtest {
public static void main(String[] args)throws Exception {
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("enter the string");
String str=br.readLine();
System.out.println("enter the character which you want");
CharSequence ch=br.readLine();
boolean bool=str.contains(ch);
System.out.println("the character found is " +bool);
int position=str.indexOf(ch.toString());
while(position>=0){
System.out.println("the index no of character is " +position);
position=str.indexOf(ch.toString(),position+1);
}
}
}
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-01-04 06:34:22
String match = "hello";
String text = "0123456789hello0123456789hello";
int j = 0;
String indxOfmatch = "";
for (int i = -1; i < text.length()+1; i++) {
j = text.indexOf("hello", i);
if (i>=j && j > -1) {
indxOfmatch += text.indexOf("hello", i)+" ";
}
}
System.out.println(indxOfmatch);
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2018-04-13 16:32:09