Splice value from an array and push spliced value into another array

Question

Hello and here is my problem.I have a task,i need to remove elements from an array and push them into another array and then return the array with removed elements. For example, in this case i have to remove all 0 values, and push them into 'a' array and then return 'a' array with there 0 values. I removed 0 values from the array by using splice method and loop, but i don't realy know how to push removed elemts into 'a' array, i've tried to use push method but i does not work for me. Hope you'll help me.Thank you everyone.

 function moveZeros(array) { var a = []; for (var i = array.length - 1; i--;) { if (array[i] == "0") { array.splice(i, 1); } } return a; } moveZeros([1, 2, 0, 1, 0, 1, 0, 3, 0, 1]); 

Answer 1

Using push should work. The .splice method will return an array with the removed elements, and you can use the spread operator ... to pass it as a set of arguments to push :

 function moveZeros(array) { var a = []; for (var i = array.length - 1; i >= 0; i--) { if (array[i] == "0") { a.push(...array.splice(i, 1)); } } return a; } const array = [0, 1, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 0]; console.log(moveZeros(array)); console.log(array) 

Finally, you should put the i-- as the final part of the loop so that it only executes when each iteration finishes (instead of as they begin). Then, change your condition to be i >= 0 so that you don't miss a zero at the front of the array.

Answer 2

Array.splice() returns an array of removed elements, and you can use Array.concat() to add them to the a array.

Notes:

1. Init i to array.length without the -1, since the condition i-- is checked before the execution of the loop's body.
2. Since the the array is iterated from end to starts, concat a to the removed elements to maintain the original order.

 function moveZeros(array) { var a = []; for (var i = array.length; i--;) { if (array[i] === 0) { a = array.splice(i, 1).concat(a); } } return a; } var result = moveZeros([1, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0]); // I've added a last 0 to the array to show that all items were removed console.log(result); 

Answer 3

You could iterate from the end and splice the array if necessary. This solution mutates the array .

 function moveZeros(array) { var i = array.length, a = []; while (i--) { if (array[i] === 0) { a.push(array.splice(i, 1)[0]); } } return a; } var array = [1, 2, 0, 1, 0, 1, 0, 3, 0, 1]; console.log(moveZeros(array)); console.log(array); 

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