我正在编写一个方法，该方法应该采用 "s1:{1,2,3,4}" 格式的输入 String 并将其放入 Set 中。我自己开发的集合类如下:
public class Set<E> implements Iterable<E> {
private static final int DEFAULT_CAPACITY = 20;
private String name;
private E[] theData;
private int size = 0;
private int capacity = 0;
public Set(){
capacity = DEFAULT_CAPACITY;
theData = (E[]) new Object[capacity];
}//end constructor
public Set(String name){
capacity = DEFAULT_CAPACITY;
theData = (E[]) new Object[capacity];
this.name = name;
}//end constructor
public String getName(){
return name;
}//end getName
public void setName(String name){
this.name = name;
}//end setName
//adds object to set
public void add(Object E) {
if (size == capacity) {
reallocate();
}//end if
theData[size] = (E) E;
size++;
for (int j = 0; j<size; j++) {
for (int k = 0; k < size; k++) {
if ((int)theData[j] < (int)theData[k]) {
E temp = theData[j];
theData[j] = theData[k];
theData[k] = temp;
}//end if
}//end nested for loop
}//end for loop
int counter = 0;
for (int i = 0; i < size; i++) {
if (E == theData[i]) {
counter++;
if (counter >= 2) {
remove((Object)E);
}//end nested if
}//end if
}//end for loop
}//end add method
public E get(int i) {
if (i < 0 || i >= size) {
throw new ArrayIndexOutOfBoundsException(i);
} else {
return theData[i];
}//end else
}//end get method
public E remove(int i) {
if (i < 0 || i >= size) {
throw new ArrayIndexOutOfBoundsException(i);
}//end if
E returnValue = theData[i];
for (int j = i + 1; j < size; j++) {
theData[j - 1] = theData[j];
}//end for loop
size--;
return returnValue;
}//end remove method
public void remove(Object E) {
for (int i = 0; i < size; i++) {
if (E == theData[i]) {
for (int j = i + 1; j < size; j++){
theData[j - 1] = theData[j];
}//end nested for loop
size--;
}//end if
}//end for loop
}//end remove method
//fix!
public int find(Object E) {
int first, last, middle;
first = 0;
last = size - 1;
middle = (first+last) / 2;
while(first <= last ) {
if ((int)theData[middle] > (int)E ) {
last = middle - 1;
} else if ((int)theData[middle] < (int)E ) {
first = middle + 1;
} else {
return middle;
}//end else
}//end while
if (first > last) {
return -1;
}//end if
return -1;
}//end find method
public Set<E> union(Set<E> s) {
Set<E> returnSet = new Set<E>();
for (int i = 0; i < this.size; i++) {
returnSet.add(this.theData[i]);
}//end for loop
for (int i = 0; i < s.size; i++) {
returnSet.add(s.theData[i]);
}//end for loop
return returnSet;
}//end union method
public Set<E> intersect(Set<E> s) {
Set<E> returnSet = new Set<E>();
for (int i = 0; i < this.size; i++) {
for (int j = 0; j < s.size; j++) {
if (this.theData[i] == s.theData[j]){
returnSet.add(theData[i]);
}//end if
}//end nested for loop
}//end for loop
return returnSet;
}//end intersect method
public Set<E> subtract(Set<E> s) {
Set<E> returnSet = new Set<E>();
for (int i = 0; i < this.size; i++) {
for (int j = 0; j < s.size; j++) {
if (this.theData[i] == s.theData[j]) {
this.remove((Object)this.theData[i]);
s.remove((Object)s.theData[j]);
}//end if
}//end nested for loop
}//end for loop
for (int i = 0; i < this.size; i++) {
returnSet.add(this.theData[i]);
}//end for loop
for (int i = 0; i < s.size; i++) {
returnSet.add(s.theData[i]);
}//end for loop
return returnSet;
}//end subtract method
public boolean equals(Set<E> s) {
boolean result = false;
for (int i = 0; i < this.size; i++) {
if (this.theData[i] == s.theData[i]) {
result = true;
}//end if
if (this.theData[i] != s.theData[i]) {
result = false;
break;
}//end if
}//end for loop
return result;
}//end equals method
private void reallocate() {
capacity = 2*capacity;
theData = Arrays.copyOf(theData, capacity);
}//end reallocate method
public String toString() {
StringBuilder set = new StringBuilder();
set.append("{");
for (int i = 0; i < size; i++) {
set.append(theData[i]);
if (i != size-1){
set.append(",");
}//end if
}//end for loop
set.append("}");
return set.toString();
}//end toString()
public SetIterator<E> iterator() {
SetIterator<E> it = new SetIterator<E>() {
private int currentIndex = 0;
public boolean hasNext() {
if (currentIndex < size && theData[currentIndex] != null){
currentIndex++;
return true;
} else{
return false;
}//end else
}//end hasNext()
public E next() {
if (!hasNext()) {
throw new NoSuchElementException();
}//end if
return theData[currentIndex++];
}//end next()
public boolean hasPrevious() {
if (currentIndex <= size && currentIndex > 0) {
currentIndex--;
return true;
} else {
return false;
}//end else
}//end hasPrevious()
public E previous() {
if (!hasPrevious()) {
throw new NoSuchElementException();
}//end if
return theData[currentIndex--];
}//end previous()
public void add(E item) {
theData[currentIndex-1] = item;
}//end add()
public void remove() {
for (int i = 0; i < size; i++) {
if (theData[currentIndex] == theData[i]) {
for (int j = i + 1; j < size; j++) {
theData[j - 1] = theData[j];
}//end nested for loop
size--;
}//end if
}//end for loop
}//end remove()
};//end new SetIterator()
return it;
}//end iterator method
}//end Set class
方法应该是
- 如果方法的格式无效，例如
"s1:[1 2,3,4}"(此示例是缺少逗号和大括号)，则会抛出异常。 - 此外，输入可以有任意数量的空格，并且仍然被视为有效。示例:
“s1: {1, 2, 3, 4 }”。
到目前为止，我所掌握的方法是:
public Set<Integer> parse(String input){
String s[] = input.split(":");
String name = s[0];
Set<Integer> returnSet = new Set<Integer>(name);
return returnSet;
}
我不确定如何正确检索字符串中集合中的元素并将它们放入 Set 对象中。我知道一旦我自己得到它们，我就可以parseInt，但我在隔离每个元素时遇到了困难。集合可以包含的元素数量没有限制；这意味着我的代码应该适用于任意数量的元素。
我也考虑过正则表达式，但我觉得好像有一种更有效的方法来做到这一点。
任何帮助将不胜感激!
最佳答案
最简单的方法是使用 Set 的构造函数
http://docs.oracle.com/javase/7/docs/api/java/util/HashSet.html
以及Arrays.asList()
http://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html
转换您的String[]进入Set<String> :
Set<String> mySet = new HashSet<String>(Arrays.asList(s));
关于java - 如何解析一个字符串的集合？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26660257/