The previous words
The previous blog post introduces object copying, and this article will introduce array copying in detail
push
function copyArray(arr){
var result = [];
for(var i = 0; i < ; i++){
(arr[i]);
}
return result;
}
var obj1=[1,2,3];
var obj2=copyArray(obj1);
(obj1); //[1,2,3]
(obj2); //[1,2,3]
(4);
(obj1); //[1,2,3]
(obj2); //[1,2,3,4]
join
The disadvantage of using this method is that all the items in the array have become strings.
function copyArray(arr){
var result = [];
result = ().split(',');
return result;
}
var obj1=[1,2,3];
var obj2=copyArray(obj1);
(obj1); //[1,2,3]
(obj2); //['1','2','3']
(4);
(obj1); //[1,2,3]
(obj2); //['1','2','3',4]
concat
function copyArray(arr){
var result = [];
result = ();
return result;
}
var obj1=[1,2,3];
var obj2=copyArray(obj1);
(obj1); //[1,2,3]
(obj2); //[1,2,3]
(4);
(obj1); //[1,2,3]
(obj2); //[1,2,3,4]
slice
function copyArray(arr){
var result = [];
result = ();
return result;
}
var obj1=[1,2,3];
var obj2=copyArray(obj1);
(obj1); //[1,2,3]
(obj2); //[1,2,3]
(4);
(obj1); //[1,2,3]
(obj2); //[1,2,3,4]
Deep copy
The above method only implements a shallow copy of the array. If you want to implement a deep copy of the array, you need to use a recursive method.
function copyArray(arr,result){
var result = result || [];
for(var i = 0; i < ; i++){
if(arr[i] instanceof Array){
result[i] = [];
copyArray(arr[i],result[i]);
}else{
result[i] = arr[i];
}
}
return result;
}
var obj1=[1,2,[3,4]];
var obj2=copyArray(obj1);
(obj1[2]); //[3,4]
(obj2[2]); //[3,4]
obj2[2].push(5);
(obj1[2]); //[3,4]
(obj2[2]); //[3,4,5]