只需要重置 Javascript 数组的索引
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Need to reset just the indexes of a Javascript array
提问by Adnan Baliwala
I have a for
loop which returns an array.
我有一个for
循环,它返回一个数组。
Return:
返回:
1st loop:
arr[0]
arr[1]
arr[2]
arr[3]
Here the length I get is 4
(Not a problem).
我得到的长度是4
(不是问题)。
Return:
返回:
2nd loop
arr[4]
arr[5]
arr[6]
arr[7]
arr[8]
Here the length I get is 9
.
我得到的长度是9
.
What I want here is the actual count of the indexes i.e I need it to be 5
. How can I do this. And is there a way that when I enter each loop every time it starts from 0
so that I get proper length in all the loops?
我在这里想要的是索引的实际计数,即我需要它5
。我怎样才能做到这一点。有没有一种方法可以让我每次开始时进入每个循环,0
以便在所有循环中获得适当的长度?
回答by Dag Sondre Hansen
This is easily done natively using Array.filter:
这很容易使用 Array.filter 本地完成:
resetArr = orgArr.filter(function(){return true;});
回答by danmcardle
You could just copy all the elements from the array into a new array whose indices start at zero.
您可以将数组中的所有元素复制到索引从零开始的新数组中。
E.g.
例如
function startFromZero(arr) {
var newArr = [];
var count = 0;
for (var i in arr) {
newArr[count++] = arr[i];
}
return newArr;
}
// messed up array
x = [];
x[3] = 'a';
x[4] = 'b';
x[5] = 'c';
// everything is reordered starting at zero
x = startFromZero(x);
回答by hallodom
Perhaps "underscore.js" will be useful here.
也许“underscore.js”在这里会有用。
The _.compact()
function returns a copy of the array with no undefined
.
该_.compact()
函数返回没有 的数组副本undefined
。
回答by M_R_K
Easy,
简单,
var filterd_array = my_array.filter(Boolean);