[英]Java Custom Comparator for sorting array of strings
在这里,我试图对开头和结尾字母相同的字符串中的单词进行排序。 它应该在适当的位置进行排序,否则不会受到干扰。
import java.util.*;
public class MyClass {
public static void main(String args[]) {
String arr[]={"zpppz","poop","zllo","bob","yea"};
Arrays.sort(arr , new Comparator<String>(){
public int compare(String a ,String b){
if((a.charAt(0) == a.charAt(a.length()-1 ) )&&(b.charAt(0)==b.charAt(b.length()-1 ) ) ){
return a.compareTo(b);
}
return 0;
}
} );
for(String s: arr ) System.out.println(s);
}
}
预期 output:“bob”“poop”“zllo”“zpppz”“是的”,但我得到 output 为:“bob”“poop”“zpppz”“zllo”“是的”
将 Comparator 与选择排序之类的东西一起使用怎么样?
public class Test {
public static void main(String args[]) {
String arr[]={"zpppz","poop","zllo","bob","yea"};
Comparator<String> comparator = new Comparator<>() {
public int compare(String a, String b) {
if ((a.charAt(0) == a.charAt(a.length() - 1)) && (b.charAt(0) == b.charAt(b.length() - 1))) {
return a.compareTo(b);
}
return 0;
}
};
selectionSort(arr, comparator);
}
static <T> void selectionSort(T[] a, Comparator<T> c) {
for (int i = 0; i < a.length; i++) {
for (int j = i; j < a.length; j++) {
if (c.compare(a[i], a[j]) > 0) {
T hold = a[i];
a[i] = a[j];
a[j] = hold;
}
}
}
}
}
结果:[鲍勃,便便,zllo,zpppz,是的]
以下代码执行您想要的操作,但不使用Comparator
。
如果不可接受,请告诉我,我将删除此答案。
private static boolean isCandidate(String word) {
boolean candidate = false;
if (word != null && word.length() > 0) {
candidate = word.charAt(0) == word.charAt(word.length() - 1);
}
return candidate;
}
/**********************************************************/
String arr[] = {"zpppz", "poop", "zllo", "bob", "yea"};
List<Integer> indexList = new ArrayList<>();
List<String> words2sort = new ArrayList<>();
for (int i = 0; i < arr.length; i++) {
if (isCandidate(arr[i])) {
indexList.add(Integer.valueOf(i));
words2sort.add(arr[i]);
}
}
if (words2sort.size() > 0) {
Collections.sort(words2sort);
int index = 0;
String[] sorted = new String[arr.length];
for (int i = 0; i < arr.length; i++) {
if (index < indexList.size() && indexList.get(index).intValue() == i) {
sorted[i] = words2sort.get(index);
index++;
}
else {
sorted[i] = arr[i];
}
}
System.out.println(Arrays.asList(sorted));
}
以上代码运行结果:
[bob, poop, zllo, zpppz, yea]
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