目录
1:
该方法有缺陷,当遍历的过程中需要删除或者添加元素,则该遍历方法有问题(此时需要使用迭代器)
private void testList(List<String> list) {
for (int i = 0; i < list.size(); i ++) {
System.out.print(list.get(i) + " ");
}
System.out.println();
}
2:
private void testList(List<String> list) {
for (String string : list) {
System.out.print(string + " ");
}
System.out.println();
}
3:
当遍历的过程中需要删除或者添加元素,推荐使用该方法
private void testList(List<String> list) {
Iterator<String> it = list.iterator();
while (it.hasNext()) {
String value = it.next();
System.out.print(value + " ");
}
System.out.println();
}
1:
该方法只能获取到value无法获取到key
private void testMap(Map<String, String> map) {
Collection<String> cMap = map.values();
for (String string : cMap) {
System.out.println(string);
}
}
2:
private void testMap(Map<String, String> map) {
Iterator<Entry<String, String>> iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
Entry<String, String> entry = iterator.next();
System.out.println(entry.getKey() + ":" + entry.getValue());
}
}
3:
private void testMap(Map<String, String> map) {
Iterator<String> it = map.keySet().iterator();
while (it.hasNext()) {
String key = it.next();
String value = map.get(key);
}
}
1:
private void testSet(Set<String> set) {
Iterator<String> it = set.iterator();
while(it.hasNext()) {
String value = it.next();
}
}
2:
private void testSet(Set<String> set) {
for (String string:set) {
value = string;
}
}