String 类的常用方法

川长思鸟来 2022-04-13 03:49 308阅读 0赞

1，求长判相等：

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		String string =reader .next();
    		int n=string .length();
    		System.out.println(n);
    		String string2 =reader.next();
    		if(string .equals(string2))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		reader.close();
    		
    	}
    }

akkhhhjjkk
    10
    akkhhhjjkk
    YES

2： 判头判尾是否相同

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .startsWith(string2))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		reader.close();
    		if(string .endsWith(string2))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    	}
    }

aaabbb
    aaa
    YES

3：判断当前字符串的某个位置间的子字符串和另一个字符串是否相等

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .regionMatches(0, string2, 0, 3))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		reader.close();
    	}
    }

eeeccc
    eee
    YES

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .regionMatches(2, string2, 0, 3))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		reader.close();
    	}
    }

eeccceee
    ccc
    YES

该方法的重载方法：（忽略大小写）

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .regionMatches(true,0, string2, 0, 3))
    		{
    			System.out.println("YES");
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		reader.close();
    	}
    }

aaaVVV
    AAA
    YES

4 判断两个字符串按字典序列比较大小

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		while(reader.hasNext())
    		{
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .compareTo(string2)==0)
    		{
    			System.out.println("YES");
    		}
    		if(string .compareTo(string2)>0)
    		{
    			System.out.println("NO I LOVE");
    		}
    		if(string .compareTo(string2)<0)
    		{
    			System.out.println("NO I DONT LOVE");
    		}
    		}
    		reader.close();
    	}
    }

aaaccc
    aaaccc
    YES
    abcde
    b
    NO I DONT LOVE
    abcde
    abbde
    NO I LOVE

5 判断当前字符串是否包含另一个字符串

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		while(reader.hasNext())
    		{
    		String string =reader .next();
    		String string2 =reader.next();
    		if(string .contains(string2))
    		{
    			System.out.println("I LOVE YOU");
    		}
    		else
    		{
    			System.out.println("I DONT LOVE YOU");
    		}
    		}
    		reader.close();
    	}
    }

aaaaaa
    ccc
    I DONT LOVE YOU
    aaaa
    a
    I LOVE YOU

6 从开端和当前位置分别检索有无此字符串：

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		while(reader.hasNext())
    		{
    		String string =reader .next();
    		String string2 =reader.next();
    		int n=string .indexOf(string2);
    		if(n!=-1)
    		{
    			System.out.println(n);
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		}
    		reader.close();
    	}
    }

aaaaaa
    cccccc
    NO
    aaaaaa
    a
    0
    aaaaaa
    bbbbaa
    NO
    abcdabd
    abd

从当前位置开始检索：

import java.util.*;
    
    public class Main 
    {
    
    	public static void main(String[] args) 
    	{
    		Scanner reader =new Scanner(System.in);
    		while(reader.hasNext())
    		{
    		String string =reader .next();
    		String string2 =reader.next();
    		int n=string .indexOf(string2,4);
    		if(n!=-1)
    		{
    			System.out.println(n);
    		}
    		else
    		{
    			System.out.println("NO");
    		}
    		}
    		reader.close();
    	}
    }

ILOVEYOU
    YOU
    5
    ILOVEYOU
    LOVE
    NO

7 获取模式串的子串：

ILOVEYOU
    LOVE

8将一个字符串去掉空格（仅限前后）：

I LOVE YOU
    I LOVE YOU
     I LOVE YOU （后面有空格）
    I LOVE YOU