是否应使用<或< =在for循环中 [英] Should one use < or <= in a for loop
问题描述
如果必须循环遍历7次，您将使用：
If you had to iterate through a loop 7 times, would you use:
for (int i = 0; i < 7; i++)
或：
for (int i = 0; i <= 6; i++)
有两个注意事项：
- 性能
- 可读性
为了提高性能，我假设使用Java或C＃。是否使用小于或小于或等于是否重要？如果您有其他语言的见解，请指出。
For performance I'm assuming Java or C#. Does it matter if "less than" or "less than or equal to" is used? If you have insight for a different language, please indicate which.
出于可读性考虑，我假设基于0的数组。
For readability I'm assuming 0-based arrays.
UPD：我提到的从0开始的数组可能会使您感到困惑。我不是在谈论遍历数组元素。只是一个一般的循环。
UPD: My mention of 0-based arrays may have confused things. I'm not talking about iterating through array elements. Just a general loop.
使用常量可以解释这个神奇的数字是一个很好的认识。因此，如果我有 int NUMBER_OF_THINGS = 7 ，那么 i< = NUMBER_OF_THINGS-1 看起来很奇怪，不是吗
There is a good point below about using a constant to which would explain what this magic number is. So if I had "int NUMBER_OF_THINGS = 7" then "i <= NUMBER_OF_THINGS - 1" would look weird, wouldn't it.
推荐答案
第一个是更多惯用。特别是，它指示（从0开始）迭代次数。当使用基于1的东西（例如JDBC，IIRC）时，我可能会想使用< =。因此：
The first is more idiomatic. In particular, it indicates (in a 0-based sense) the number of iterations. When using something 1-based (e.g. JDBC, IIRC) I might be tempted to use <=. So:
for (int i=0; i < count; i++) // For 0-based APIs
for (int i=1; i <= count; i++) // For 1-based APIs
我希望在实际代码中，性能差异不会很小。
I would expect the performance difference to be insignificantly small in real-world code.
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