split an array into two based on a index in javasc

问题:

I have an array with a list of objects. I want to split this array at one particular index, say 4 (this in real is a variable). I want to store the second part of the split array into another array. Might be simple, but I am unable to think of a nice way to do this.

回答1:

Use slice, as such:

var ar = [1,2,3,4,5,6];

var p1 = ar.slice(0,4);
var p2 = ar.slice(4);

回答2:

You can use Array@splice to chop all elements after a specified index off the end of the array and return them:

x = ["a", "b", "c", "d", "e", "f", "g"];
y = x.splice(3);
console.log(x); // ["a", "b", "c"]
console.log(y); // ["d", "e", "f", "g"]

回答3:

use slice:

var bigOne = [0,1,2,3,4,5,6];
var splittedOne = bigOne.slice(3 /*your Index*/);

回答4:

I would recommend to use slice() like below

ar.slice(startIndex,length); or ar.slice(startIndex);

var ar = ["a","b","c","d","e","f","g"];

var p1 = ar.slice(0,3);
var p2 = ar.slice(3);

console.log(p1);
console.log(p2);

回答5:

You can also use underscore/lodash wrapper:

var ar = [1,2,3,4,5,6];
var p1 = _.first(ar, 4);
var p2 = _.rest(ar, 4);

回答6:

Simple one function from lodash: const mainArr = [1,2,3,4,5,6,7] const [arr1, arr2] = _.chunk(mainArr, _.round(mainArr.length / 2));