在 JavaScript 中增加变量的其他方法
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Other ways to increment a variable in JavaScript
提问by Daniel Attfield
Possible Duplicate:
Why avoid increment (“++”) and decrement (“--”) operators in JavaScript?
I'm a big fan of Douglas Crockford and his excellent book, JavaScript: The Good Parts. I also use his JSLinttool on an hourly basis before checking in any code to our repository, as is good sense.
我是 Douglas Crockford 和他的优秀著作JavaScript: The Good Parts 的忠实粉丝。在将任何代码签入我们的存储库之前，我还每小时使用他的JSLint工具，这很有意义。
One thing I've noticed when running code through JSLint is its insistence that the ++ increment operator is somehow evil. I know I can turn certain rules off, but that's cheating ;). Crockford mentions his dislike on page 112 of JS: TGP...
在通过 JSLint 运行代码时，我注意到的一件事是它坚持认为 ++ 增量运算符在某种程度上是邪恶的。我知道我可以关闭某些规则，但那是作弊；)。Crockford 在 JS: TGP 的第 112 页提到了他的不喜欢...
In my own practice, I observed that when I used ++ and --, my code tended to be too tight, too tricky, too cryptic. So, as a matter of discipline, I don't use them any more. I think that as a result, my coding style has become cleaner.
在我自己的实践中，我观察到当我使用 ++ 和 -- 时，我的代码往往过于紧凑、过于棘手、过于神秘。所以，作为纪律问题，我不再使用它们。我认为因此，我的编码风格变得更清晰了。
That's all very lovely, but he doesn't give any examples of the way he codes them now. I assume he's doing something like...
这一切都非常可爱，但他没有给出任何关于他现在编码方式的例子。我猜他正在做类似的事情...
var i;
i = 0;
i = i + 1;
Again, great, but I've got a few basic 'for loops' in my JS code, as I imagine many people have, and I've always used the standard syntax...
再次，很好，但是我的 JS 代码中有一些基本的“for 循环”，我想很多人都有，而且我一直使用标准语法......
for (i = 0; i < myArray.length; i++) {
// Loop Stuff
}
Am I missing something? What's the cleanest and/or best way to increment/decrement?
我错过了什么吗？增加/减少的最干净和/或最好的方法是什么？
回答by b_erb
I think this is rather controversial, and I personally stick to i++in loops. Of cource, you can replace it with i = i + 1in your loop statement, to be fully compliant to JSLint.
我认为这是相当有争议的，我个人坚持i++循环。当然，您可以i = i + 1在循环语句中替换它，以完全符合 JSLint。
There aren't real alternatives to increment and decrement numerical values in JavaScript. You can often use Array.forEach()and/or Object.keys()in order to prevent numerical indexes.
在 JavaScript 中增加和减少数值没有真正的替代方案。您可以经常使用Array.forEach()和/或Object.keys()来防止数字索引。
回答by ascanio
The only tricky thing I see in autoincrement/decrement operators (and I'm quite surprised that no one here pointed that out) is the difference between prefix (++i) and postfix (i++) versions. I also believe that autoincrement/decrement operators are slightly more efficient, in general. Besides this, I think the choice is based mainly on aesthetics, especially in javascript.
我在自增/自减运算符中看到的唯一棘手的事情（我很惊讶这里没有人指出这一点）是前缀 (++i) 和后缀 (i++) 版本之间的区别。我也相信自动递增/递减运算符的效率一般稍高一些。除此之外，我认为选择主要基于美学，尤其是在 javascript 中。
回答by Alvin
to pass JSLint I now always do:
通过 JSLint 我现在总是这样做：
for (var i = 0; i < myArray.length; i+=1) {
// Loop Stuff
}
回答by Kevin Bowersox
Personally, I see nothing wrong with the ++/-- operators for incrementing and decrementing. While something like i = i + 1;may be easier for new coders, the practice is not rocket science once you know what the operators stand for.
就个人而言，我认为 ++/-- 运算符用于递增和递减没有任何问题。虽然i = i + 1;对于新的编码员来说类似的事情可能更容易，但一旦你知道操作员代表什么，这种做法就不是火箭科学。
回答by Shadow Wizard is Ear For You
Regarding loop, one original idea can be using such loop to avoid all kinds of numbers:
关于循环，一个原始想法可以使用这样的循环来避免各种数字：
var a = [];
for (var i in " ")
a.push("Loop iteration here");
alert(a.join("\n"));
Meaning iterate over a string, there will be amount of iterations equal to the string length - 5 in the above example.
意思是迭代一个字符串，在上面的例子中，迭代次数等于字符串长度 - 5。
Live test case: http://jsfiddle.net/vTFDP/
现场测试用例：http: //jsfiddle.net/vTFDP/
回答by spraff
In C/C++ this is important, especially with arbitrary iterators and pre/post increment semantics. Also, random access vs forward-iterators.
在 C/C++ 中，这很重要，尤其是对于任意迭代器和前/后增量语义。此外，随机访问与前向迭代器。
In Javascript it's more about aesthetics than anything else. Unless you're dealing with strings. "1"+1is "11".
在 Javascript 中，它更多地是关于美学的。除非你正在处理字符串。"1"+1是“11”。
I would say that ++i is an idiom that's worth being consistent with.
我会说 ++i 是一个值得保持一致的习语。
JSLint is wrong.
JSLint 是错误的。
