java将字符串存储在char数组中

Question

In Java, How can I store a string in an array? For example:

//pseudocode:
name = ayo
string index [1] = a
string index [2] = y
string index [3] = o

Then how can I get the length of the string?

// this code doesn't work
String[] timestamp = new String[40]; String name;
System.out.println("Pls enter a name and surname");
Scanner sc = new Scanner(System.in);
name = sc.nextLine();
name=timestamp.substring(0, 20);

Answer 1

If you want a char array to hold each character of the string at every (or almost every index), then you could do this:

char[] tmp = new char[length];
for (int i = 0; i < length; i++) {
    tmp[i] = name.charAt(i);
}

Where length is from 0 to name.length .

Answer 2

This code doesn't compile because the substring method can only be called on a String, not a String array if I'm not mistaken. In the code above, timestamp is declared as a String array with 40 indexes.

Also in this code, you're asking for input from a user and assigning it to name in this line:

name = sc.nextLine();

and then you are trying to replace what the user just typed with what is stored in timestamp on the next line which is nothing, and would erase whatever was stored in name:

name = timestamp.substring(0,20);

And again that wouldn't work anyway because timestamp is an array of 40 strings instead of one specific string. In order to call substring it has to be just one specific string.

I know that probably doesn't help much with what you're trying to do, but hopefully it helps you understand why this isn't working.

If you can reply with what you're trying to do with a specific example I can help direct you further. For example, let's say you wanted a user to type their name, "John Smith" and then you wanted to seperate that into a first and last name in two different String variables or a String array. The more specific you can be with what you want to do the better. Good luck :)

BEGIN EDIT

Ok here are a few things you might want to try if I understand what you're doing correctly.

//Since each index will only be holding one character, 
//it makes sense to use char array instead of a string array.
//This next line creates a char array with 40 empty indexes.
char[] timestamp = new char[40];

//The variable name to store user input as a string. 
String name;

//message to user to input name  
System.out.println("Pls enter a name and surname");

//Create a scanner to get input from keyboard, and store user input in the name variable  
Scanner sc = new Scanner(System.in);  
name = sc.nextLine();

//if you wanted the length of the char array to be the same
//as the characters in name, it would make more sense to declare it here like this
//instead of declaring it above.
char[] timestamp = new char[name.length()];


//For loop, loops through each character in the string and stores in
//indexes of timestamp char array. 
for(int i=0; i<name.length;i++)
{
    timestamp[i] = name.charAt(i);
}

The other thing you could do if you wanted to just seperate the first and last name would be to split it like this.

String[] seperateName = name.split(" ");

That line will split the string when it finds a space and put it in the index in the seperateName array. So if name was "John Smith", sperateName[0] = John and seperateName[1] = Smith.

Answer 3

Java, substring an array:

Use Arrays.copyOfRange:

public static <T> T[] copyOfRange(T[] original,
                                  int from,
                                  int to)

For example:

import java.util.*;
public class Main{
    public static void main(String args[]){
        String[] words = new String[3];
        words[0] = "rico";
        words[1] = "skipper";
        words[2] = "kowalski";

        for(String word : words){
            System.out.println(word);
        }   
        System.out.println("---");

        words = Arrays.copyOfRange(words, 1, words.length);
        for(String word : words){
            System.out.println(word);
        }   
    }   
}

Prints:

rico
skipper
kowalski
---
skipper
kowalski

Another stackoverflow post going into more details: https://stackoverflow.com/a/6597591/445131

Answer 4

Are you looking for a char[] ? You can convert a character array to a String using String.copyValueOf(char[]) .