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ArrayList在内循环中删除
1.The iterators returned by this class's iterator and listIterator methods are fail-fast: if the list is structurally modified at any time after the iterator is created, in any way except through the iterator's own remove or add methods, the iterator will throw a ConcurrentModificationException.
参考：http://stackoverflow.com/quest…
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| import java.util.*; | |
| public class ArrayListExamples { | |
| public static void main(String args[]) { | |
| // Creating an empty array list | |
| ArrayList<String> list = new ArrayList<String>(); | |
| // Adding items to arrayList | |
| list.add("Item1"); | |
| list.add("Item2"); | |
| list.add(2, "Item3"); // it will add Item3 to the third position of | |
| // array list | |
| list.add("Item4"); | |
| // Display the contents of the array list | |
| System.out.println("The arraylist contains the following elements: " | |
| + list); | |
| // Checking index of an item | |
| int pos = list.indexOf("Item2"); | |
| System.out.println("The index of Item2 is: " + pos); | |
| // Checking if array list is empty | |
| boolean check = list.isEmpty(); | |
| System.out.println("Checking if the arraylist is empty: " + check); | |
| // Getting the size of the list | |
| int size = list.size(); | |
| System.out.println("The size of the list is: " + size); | |
| // Checking if an element is included to the list | |
| boolean element = list.contains("Item5"); | |
| System.out.println("Checking if the arraylist contains the object Item5: " | |
| + element); | |
| // Getting the element in a specific position | |
| String item = list.get(0); | |
| System.out.println("The item is the index 0 is: " + item); | |
| // Retrieve elements from the arraylist | |
| // 1st way: loop using index and size list | |
| System.out | |
| .println("Retrieving items with loop using index and size list"); | |
| for (int i = 0; i < list.size(); i++) { | |
| System.out.println("Index: " + i + " - Item: " + list.get(i)); | |
| } | |
| // 2nd way:using foreach loop | |
| System.out.println("Retrieving items using foreach loop"); | |
| for (String str : list) { | |
| System.out.println("Item is: " + str); | |
| } | |
| // 3rd way:using iterator | |
| // hasNext(): returns true if there are more elements | |
| // next(): returns the next element | |
| System.out.println("Retrieving items using iterator"); | |
| for (Iterator<String> it = list.iterator(); it.hasNext();) { | |
| System.out.println("Item is: " + it.next()); | |
| } | |
| // Replacing an element | |
| list.set(1, "NewItem"); | |
| System.out.println("The arraylist after the replacement is: " + list); | |
| // Removing items | |
| // removing the item in index 0 | |
| list.remove(0); | |
| // removing the first occurrence of item "Item3" | |
| list.remove("Item3"); | |
| System.out.println("The final contents of the arraylist are: " + list); | |
| // Converting ArrayList to Array | |
| String[] simpleArray = list.toArray(new String[list.size()]); | |
| System.out.println("The array created after the conversion of our arraylist is: " | |
| + Arrays.toString(simpleArray)); | |
| } | |
| } |
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| import java.util.*; | |
| class Test { | |
| public static ArrayList<String> removeBad(ArrayList<String> phrases){ | |
| for(String aPhrase:phrases) | |
| { | |
| if(aPhrase.indexOf("bad")>=0){ | |
| //phrases.remove(aPhrase); | |
| System.out.println(aPhrase); | |
| } | |
| } | |
| return phrases; | |
| } | |
| public static void main(String[] args) { | |
| ArrayList<String> phrases = new ArrayList<String>(); | |
| phrases.add("good day"); | |
| phrases.add("bad hair"); | |
| phrases.add("cookie are good"); | |
| phrases.add("bad applies"); | |
| removeBad(phrases); | |
| System.out.print(phrases); | |
| } | |
| } |
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| import java.util.*; | |
| class Test { | |
| public static ArrayList<String> removeBad(ArrayList<String> phrases){ | |
| int size = phrases.size(); | |
| System.out.println(size); | |
| for(int i = size - 1; i>=0; i--) | |
| { | |
| if(phrases.get(i).indexOf("bad")>=0){ | |
| System.out.println(phrases.get(i)); | |
| phrases.remove(i); | |
| } | |
| } | |
| return phrases; | |
| } | |
| public static void main(String[] args) { | |
| ArrayList<String> phrases = new ArrayList<String>(); | |
| phrases.add("good day"); | |
| phrases.add("bad hair"); | |
| phrases.add("cookie are good"); | |
| phrases.add("bad applies"); | |
| removeBad(phrases); | |
| System.out.print(phrases); | |
| } | |
| } |
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