javascript 将空数组作为数组键的值推送
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原文地址: http://stackoverflow.com/questions/7549816/
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push empty array as value of an array key
提问by itsme
I need to push a new array as the value of a parent array key.
我需要推送一个新数组作为父数组键的值。
this is my array.
这是我的阵列。
asd[
[hey],
[hi]
]
i would like to return.
我想回来。
asd[
[hey]=>[],
[hi]
]
i do:
我做：
var asd = new Array();
asd.push(hey);
asd.push(hi);
asd[hey].push(new Array());
so obviously is not ok my code
回答by Hubro
Instead of new Array();you should just write []. You can create a nested array like this
而不是new Array();你应该只写[]. 您可以像这样创建嵌套数组
myarray =
[
"hey",
"hi",
[
"foo"
]
]
Remember that when you push things into an array, it's given a numerical index. Instead of asd[hey]write asd[0]since heywould have been inserted as the first item in the array.
请记住，当您将事物推入数组时，它会被赋予一个数字索引。而不是asd[hey]writeasd[0]因为hey将作为数组中的第一项插入。
回答by derp
You could do something like this:
你可以这样做：
function myArray(){this.push = function(key){ eval("this." + key + " = []");};}
//example
test = new myArray();
//create a few keys
test.push('hey');
test.push('hi');
//add a value to 'hey' key
test['hey'].push('hey value');
// => hey value
alert( test['hey'] );
Take notice that in this example testis not an arraybut a myArrayinstance.
请注意，在这个例子test中不是一个array而是一个myArray实例。
If you already have an array an want the values to keys:
如果您已经有一个数组并希望将值设置为键：
function transform(ary){
result= [];
for(var i=0; i< ary.length; i++){result[ary[i]] = [];}
return result;
}
//say you have this array
test = ['hey','hi'];
//convert every value on a key so you have 'ary[key] = []'
test = transform(test);
//now you can push whatever
test['hey'].push('hey value');
// => hey value
alert( test['hey'] );
In this case testremains an array.
在这种情况下test仍然是array.
