Java determines whether a string contains a certain character (string)
Nov 21, 2019 am 10:32 AM
Java method to determine whether a string contains a certain string:
1. startsWith()
This method has two variants and tests If a string starts at the specified index the specified prefix or by default starts at the string position
The syntax defined for this method is as follows:
public boolean startsWith(String prefix, int toffset) or public boolean startsWith(String prefix)
prefix – The prefix to match. Here are the details of the parameters:
toffset – where to start looking for the string.
The return value is true and false
import java.io.*;
public class Test{
public static void main(String args[]){
String Str = new String("Welcome to Yiibai.com");
System.out.print("Return Value :" );
System.out.println(Str.startsWith("Welcome") );
System.out.print("Return Value :" );
System.out.println(Str.startsWith("Tutorials") );
System.out.print("Return Value :" );
System.out.println(Str.startsWith("Yiibai", 11) );
}
}2. contains method
java.lang.String.contains()
The method returns true when and Only if this string contains the specified char value sequence
The return value is true and false
public static void main(String[] args) {
String str = "abc";
boolean status = str.contains("a");
if(status){
System.out.println("包含");
}else{
System.out.println("不包含");
}
}3, indexOf method
java.lang.String.indexOf() The purpose is to find the position of a word in a string, and at the same time, it can also determine whether a string contains a certain character.
The return value of indexOf is int
public static void main(String[] args) {
String str1 = "abcdefg";
int result1 = str1.indexOf("ab");
if(result1 != -1){
System.out.println("字符串str中包含子串“ab”"+result1);
}else{
System.out.println("字符串str中不包含子串“ab”"+result1);
}
}For more java knowledge, please Follow java basic tutorial.
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