jQuery 如何使用jquery创建动态变量？
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How to create dynamic variables using jquery?
提问by Deepak A
I want some jquery variables to be created dynamically. In my code I am having a loop, and with the loop values I want to create some variables. Here is my sample code.
我想要动态创建一些 jquery 变量。在我的代码中，我有一个循环，并且我想使用循环值创建一些变量。这是我的示例代码。
array=["student","parent","employee"]
$.each(user_types, function( index, value ){
var value+"_type" // this is the type of variable i want to build.
})
I have found about evalfunction. That code goes like this.
我发现了eval函数。那个代码是这样的。
var type = "type"
eval("var pre_"+type+"= 'The value of dynamic variable, val';");
alert(pre_type) // this gives 'The value of dynamic variable, val' in alert box.
Is there any alternate ways as I have read the eval function is not prefered while coding .jsfiles.
是否有其他替代方法，因为我已经阅读了 eval 函数在编码.js文件时不是首选。
回答by George
Any time you find yourself using a variable in the name of a variable, you probably want to use an object literal. Create the object with curly braces {}, and then set the object property key using square bracket notation:
每当您发现自己在变量名中使用变量时，您可能想要使用对象字面量。使用花括号创建对象{}，然后使用方括号表示法设置对象属性键：
var user_types = ["student","parent","employee"];
var types = {};
$.each(user_types, function( index, value ){
types[value] = 'The value of dynamic variable, val';
});
Note: You haven't tagged it, but I assume because you've used each()that you are using jQuery, please correct me if I'm wrong.
注意：您没有标记它，但我假设因为您已经使用each()过您正在使用 jQuery，如果我错了，请纠正我。
回答by Tibos
First of all i must say that i can't think of any reason why you want to do this.
首先，我必须说，我想不出你为什么要这样做的任何理由。
If you really need to have those variables, in global scope, you can do the following:
如果您确实需要在全局范围内拥有这些变量，则可以执行以下操作：
var array=["student","parent","employee"]
array.forEach(function(value){
window[value+"_type"] = 'My value ' + value;
});
console.log(student_type);
console.log(parent_type);
console.log(employee_type);
If you don't want the variables in global scope, i'm afraid i don't know an elegant solution.
如果您不想在全局范围内使用变量，恐怕我不知道一个优雅的解决方案。
I used array.forEachinstead of your jQuery loop because the problem is not related to jQuery at all and because i don't think you said enough of your logic to make a coherent example.
我使用array.forEach了你的 jQuery 循环而不是你的 jQuery 循环，因为这个问题根本与 jQuery 无关，而且因为我认为你没有足够的逻辑来制作一个连贯的例子。
EDIT: I should make it clear that while the 'variables' created behave mostly like other variables in global scope, they are NOT variables. Here is how they differ:
编辑：我应该明确指出，虽然创建的“变量”的行为与全局范围内的其他变量大致相同，但它们不是 variables。以下是它们的不同之处：
// Difference 1: hoisting
console.log(x); // undefined
console.log(y); // ReferenceError: y is not defined
var x = 5;
window[y] = 5;
console.log(x); // 5
console.log(y); // 5
// Difference 2: [[Configurable]]
delete x;
delete y;
console.log(x); // 5
console.log(y); // ReferenceError: y is not defined
