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This article mainly explains "what is the difference between for and foreach in Java". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "what is the difference between for and foreach in Java?"

(1) traversing elements

First of all, let's take each piece of code as an example:

String [] array = {"1", "2", "3"}; for (String I: array) {System.out.println (I);} ArrayList list = new ArrayList (); list.add ("111"); list.add (" 222"); list.add ("333") For (String I: list) {System.out.println (I);}

The result after traversal is as follows:

one

two

three

one hundred and eleven

two hundred and twenty two

three hundred and thirty three

There is no doubt about the result.

Let's take a look at the compiled source code (idea comes with it, just open your class source file in the target package):

String [] array = new String [] {"1", "2", "3"}; String [] var2 = array; int var3 = array.length; for (int var4 = 0; var4 < var3; + + var4) {String I = var2 [var4]; System.out.println (I);} ArrayList list = new ArrayList (); list.add List.add; list.add (333); Iterator var7 = list.iterator (); while (var7.hasNext ()) {String I = (String) var7.next (); System.out.println (I);}

As you can see, the traversal array uses the original for loop, and the collection uses the Iterator iterator.

(2) Delete elements

Oh, k! Next, let's delete the element:

Use a for loop:

ArrayList list = new ArrayList (); list.add; list.add; list.add (333); log.info (list.toString ()); for (int I = 0; I

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