2023-05-11 javascript

members=[
'kim',
'choi',
'park'
];

members.splice(1,2);

We delete elements of array using splice method. We first put the starting index as a first parameter, and the number of element that we want to delete as a second parameter. Meanwhile, the meaning of splice(1,2) is delete 2 elements from starting index 1. Therefore, only 'kim' will remain after the splice method is executed.

members.splice(1,2,'Lee');

If there is a third parameter, we insert a value to where we delete elements. Therefore, 'kim', 'lee' will remain after the splice method is ececuted.

members.splice(1,1,'Lee');

change 1st index value to 'Lee'.

members.splice(1,2,'Lee','Han');

change multiple values at once.

//members.splice(-1,1);
members.splice(members.length - 1,1);

use a second sentence not a first sentence to delete a last element in array.

numbers.splice(0, 0, 1, 2, 3, 5, 8, 9);

We can add multiple elements like this. It means delete 0 element from starting index 0. Therefore, delete no elements and add 6 elements(1, 2, 3, 5, 8, 9).

let j=0;
let len=numbers.length;

for(let i=0;i<len;i++){
  if(numbers[j]%2===1){
    numbers.splice(j,1);
  }else{
    j=j+1;
  }
}

instead of this code,

for (let i = 0; i < numbers.length; i++) {
  if (numbers[i] % 2 !== 0) {
    numbers.splice(i, 1);
    i--;
  }
}

use this code. Keep in mind that we can do - i as well.