从数组中删除数字-Javascript

Question

I am writing a script where I have to randomly generate a number from an array and then remove the number so that it cannot be generated again. What appears to be happening is that the number generated, after being spliced, is removing other numbers from my array. I assume it is being subtracted. Here is the necessary code:

    var randNum = [0,1,2,3,4,5,6,7,8,9];

    function clickHandler ()
        {
            output = randNum[Math.floor(Math.random() * randNum.length)];
            console.log("This is the generated number:" + output);
            randNum.splice(output);
            console.log("This is the resulting array without the generated number:" + randNum);


        }

Answer 1

You mix up value and index.

Array#splice needs a count for splicing elements. If not supplied, splice splices all items from the given index to the end.

 var randNum = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; function clickHandler() { var index = Math.floor(Math.random() * randNum.length); console.log("This is the generated number: " + randNum[index]); randNum.splice(index, 1); console.log("This is the resulting array without the generated number: " + randNum); } clickHandler(); clickHandler(); 

Answer 2

Use randNum.splice(index, 1); to remove only one number from array

If deleteCount is omitted, or if its value is larger than array.length - start (that is, if it is greater than the number of elements left in the array, starting at start), then all of the elements from start through the end of the array will be deleted

MDN

Answer 3

This is another way of doing it.

    let numbersLeft = [0,1,2,3,4,5,6,7,8,9];
    let numbersPulled = [];

    function generateNumber(){
      let randomNumber = randNum[Math.floor(Math.random() * randNum.length)];
      return randomNumber;
    }

    function clickHandler () {
      let numberToPull = generateNumber();
      if ( numbersPulled.indexOf(numberToPull) != -1){
        numbersLeft.splice(numberToTest, 0);
        numbersPulled.push(numberToTest);
      } else {
        console.log('That number has already been pulled!');
      }
    }