我应该在for-each循环中初始化数组？

Question

以下是否会产生不必要的内存使用

    String[] words = text.split(" ");
    for (String s : words)
    {...}

或者text.split(" ")每次循环重复时都会调用以下内容

    for (String s : text.split(" "))
    {...}

哪种方式更可取？

Answer 1

There are pluses to each way of writing your loop:

• The first way is more debuggable: you can set a breakpoint on the for, and inspect words
• The second way avoids introducing a name words into the namespace, so you can use the name elsewhere.

As far as performance and readability go, both ways are equally good: the split will be called once before the start of the loop, so there are no performance or memory usage consequences to using the second code snippet.