javascript 在循环中连接 var
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concatenate var in loop
提问by user947462
A basic question please, I am trying this code:
请提出一个基本问题，我正在尝试以下代码：
var number_questions = postsJSON1[i]['question'].length;
for (a=0; a<number_questions; a++) {
var post+[a] = postsJSON1[i]['question'][a];
}
this line give an error: var post+[a]
这一行给出了一个错误： var post+[a]
What is the correct way ?
什么是正确的方法？
回答by PeeHaa
This will get you an array:
这将为您提供一个数组：
var number_questions = postsJSON1[i]['question'];
var post = [];
for (a=0; a<number_questions; a++) {
post[a] = postsJSON1[i]['question'][a];
}
This will get you a string:
这会给你一个字符串：
var number_questions = postsJSON1[i]['question'];
var post = '';
for (a=0; a<number_questions; a++) {
post += postsJSON1[i]['question'][a];
}
BTW I don't know the contents of postsJSON1[i]['question'], but the following looks a bit weird:
顺便说一句，我不知道 的内容postsJSON1[i]['question']，但以下内容看起来有点奇怪：
var number_questions = postsJSON1[i]['question'];
Shouldn't that be:
不应该是：
var number_questions = postsJSON1[i]['question'].length;
?
?
回答by Wayne
It's hard to see exactly what you're trying to do, but I think you want this:
很难确切地看到你想要做什么，但我认为你想要这个：
var number_questions = postsJSON1[i]['question'].length;
var post = "";
for (a = 0; a < number_questions; a++) {
post += postsJSON1[i]['question'][a];
}
I'm assuming that postsJSON1[i]['question']is an array, since you're treating it as such in the body of the loop. That's why I've changed the first line to use the lengthproperty to init number_questions.
我假设这postsJSON1[i]['question']是一个数组，因为您在循环体中是这样对待它的。这就是为什么我将第一行更改为使用该length属性的原因 init number_questions。
By the way, this code is functionally equivalent to join; you could do the same thing in one line:
顺便说一下，这段代码在功能上等同于join; 你可以在一行中做同样的事情：
var post = postsJSON1[i]['question'].join("");
