如何修复错误：Map 类型中的 put(Integer, Integer) 方法<integer,integer>不适用于 arguments (int, String)</integer,integer>

Question

I don't know how to fix this. I want to intake a certain number of strings with a hashmap. I am still a beginner coder and just learned hashmap. PLS help.

public class Hashmap {
public static void main(String[] args) {
    Scanner Scanner = new Scanner(System.in);
    int lines = Scanner.nextInt();
    Map<Integer, Integer> hash = new HashMap<Integer, Integer>();
    for (int i = 0; i < lines; i++) {
        hash.put(i, Scanner.next());
    }
}

}

Answer 1

Scanner.next returns a String object. You cannot put a String as the value in a map you declared as taking Integer objects for values. Square peg, round hole.

You have a choice of three ways to fix.

You could change your map declaration to take String objects as the value. Change this:

Map< Integer , Integer > map = new HashMap<>();

… to:

Map< Integer , String > map = new HashMap<>();

Or, you can collect integers from the Scanner rather than text. Call Scanner#nextInt .

Or, you can collect text from the scanner, and then transform that text to an integer. Call Integer.valueOf .