CODEWITHSUNDEEP
javaarraysstring
J.user94
J.user94

Reputation: 81

Removing the last comma

I'm trying to remove the last comma from my print method. Is there a way to do this? Thank you.

    public void print() {
    for(int i = 0; i < M.length; i++){
        for(int j = 0; j < M[i].length; j++){
            System.out.print(M[i][j] + ",");
        }
        System.out.println();
    }

}

Output:

1.5,2.0,3.0,

3.0,2.5,4.0,

2.5,4.0,2.5,

I ended up adding an "if" statement to solve the same problem. Here is how I ended up doing it:

    public void print() {
    for(int i = 0; i < M.length; i++){
        for(int j = 0; j < M[i].length; j++){
            if(j == M[i].length-1){
                System.out.print(M[i][j] +" ");
            }
            else{
                System.out.print(M[i][j] + ",");
            }
        }
        System.out.println();
    }

}

Output:

1.5,2.0,3.0

3.0,2.5,4.0

2.5,4.0,2.5

Upvotes: 3

Views: 1764

Answers (6)

F. Tu
F. Tu

Reputation: 21

You should use an if else statement in your second for loop. And instead of putting the comma at the back, it's better to put it at the front. The sample code looks like this:

public void print(){
    int[][] M = {{1,3},{2,3,4},{5,6},{5,2}};
    for(int i = 0; i < M.length; i++){
        for(int j = 0; j < M[i].length; j++){
            if (j==0)
                System.out.print(M[i][j]);
            else
                System.out.print(","+M[i][j]);
        }
        System.out.println();
    }

}

The code will output

1,3

2,3,4

5,6

5,2

Upvotes: 2

Tong Liu
Tong Liu

Reputation: 16

Here's a cool Java 8 way of doing it if you like streams. Works with arrays of int/double :D

Arrays.stream(M)
      .map(x -> Arrays.stream(x)
                  .mapToObj(String::valueOf)
                  .collect(Collectors.joining(",")))
      .forEach(System.out::println);

Upvotes: 0

Kenny Togunloju
Kenny Togunloju

Reputation: 189

You can try this

public void print() {
for(int i = 0; i < M.length; i++){
    for(int j = 0; j < M[i].length; j++){
        System.out.print(M[i][j]);
       if (i < M.length-1 || j < M[i].length - 1) {
          System.out.print(",")
       }
    }
    System.out.println();
}
}

Basically it checks if the element is the last in the array and if not, it prints the comma. if it is it doesn't print the comma. Hope this helps

Upvotes: 1

Chai T. Rex
Chai T. Rex

Reputation: 3020

You can use "," before the item instead of after, and simply don't print it before the first item:

public void print() {
    for (int i = 0; i < M.length; i++) {
        if (M[i].length != 0) {
            System.out.print(M[i][0]);
        }
        for(int j = 1; j < M[i].length; j++) {
            System.out.print("," + M[i][j]);
        }
        System.out.println();
    }
}

You might also want to store the row in a variable so that you don't keep accessing the ith element of M repeatedly:

public void print() {
    for (int i = 0; i < M.length; i++) {
        final type[] row = M[i];
        if (row.length != 0) {
            System.out.print(row[0]);
        }
        for(int j = 1; j < row.length; j++) {
            System.out.print("," + row[j]);
        }
        System.out.println();
    }
}

Upvotes: 0

leeyuiwah
leeyuiwah

Reputation: 7152

I often use this idiom for this problem -- make a variable comma special ("") for the first time, and then restore it to the normal state (", ") for the second time and onward:

public void print() {
    for(int i = 0; i < M.length; i++){
        String comma = "";      // first time special
        for(int j = 0; j < M[i].length; j++){
            System.out.print(comma + M[i][j]);
            comma = ",";        // second time onward
        }
        System.out.println();
    }

}

Upvotes: 3

Gab
Gab

Reputation: 1017

In your second for loop, add an if statement that checks to see if it's the last item of the list. If it is, omit the comma. Else, put the comma.

Upvotes: 1

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