Java HashSet：如果HashSet包含的值不是指定的值，则返回false
所以我从JSON请求中提取了一个字符串列表，例如{ADD，DEL，CHG，DEL，NA，ADD，BLAH，YAK，…}，并将它们传递到哈希集以避免重复。 如果HashSet除了ADD或NA或两者之外还有其他内容，如何让函数返回false？ 谢谢你的帮助Java HashSet：如果HashSet包含的值不是指定的值，则返回false,java,hashset,Java,Hashset,所以我从JSON请求中提取了一个字符串列表，例如{ADD，DEL，CHG，DEL，NA，ADD，BLAH，YAK，…}，并将它们传递到哈希集以避免重复。 如果HashSet除了ADD或NA或两者之外还有其他内容，如何让函数返回false？ 谢谢你的帮助 import java.util.HashSet; import java.util.Set; public class HashSetTheory {
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
另外：我的真实条件是，当NA是可选的时，ADD必须始终存在。除了强制的ADD和可选的NA之外，不能存在其他值。 例如：
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
private boolean isAddOrNa(List<AllActions> allActions) {
Set<String> actions = new HashSet<>();
for (com.demo.Action action : allActions) {
actions.add(action.getName());
}
return ((actions.size() <= 2) && (actions.contains("ADD") || actions.contains("NA"))) &&
!(actions.contains("DEL") || actions.contains("CHG") || actions.contains("BLAH") || actions.contains("YAK"));
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
我不知道你的列表有多大，也不知道你的意图是什么，但根据你提供的信息，一个简单的解决方案是在哈希集上搜索3个选定的单词，并使用计数器跟踪点击。然后将其与HashSet的大小进行比较。ifhashSet.containsADD | | HashSet.containsNA
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
使用它，谢谢问题的解决方案是检查输入集中是否存在NA和添加的任何其他内容。这可以通过将输入集与验证集一起添加来实现，如果在输入集中找不到新元素，则为false，否则为true：
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
据我所知，您希望为您的集合提供验证方法。例如，如果JSON中的列表仅仅是{ADD，NA，ADD}，那么就可以了，您的方法应该返回true。如果列表中有其他值，如问题中的示例，则应返回false
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
private static boolean setHasOnlySpecifiedValues(
Set<String> specifiedValues, Set<String> setToCheck) {
// we check setToCheck by removing specifiedValues and seeing if there are any
// values left: however, the caller may be surprised if we remove elements from
// the set passed to us, so work on a copy instead
Set<String> workingCopy = new HashSet<>(setToCheck);
workingCopy.removeAll(specifiedValues);
if (workingCopy.isEmpty()) { // there were only specified values
return true;
} else {
System.out.println("The set contained other values: " + workingCopy);
return false;
}
}
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
The set contained other values: [YAK, CHG, DEL, BLAH]
The result of the check is: false
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}
尽量减少条件。这有帮助吗？到目前为止您尝试了什么？发布你的代码！你运行它时发生了什么？你以为会发生什么？你具体有什么问题？两者都有还是两者都有？两者都有。如果你的目标是混淆，你肯定成功了……请阅读。不要仅仅因为你还没有必要的代表就发表评论作为答案。“不要滥用这个系统。恕我不敢苟同，@JimGarrison。”。这确实回答了所问的问题。此外，它并没有免费提供代码，坦率地说，OP不值得花这么少的精力来演示。我们可以讨论这是否是该问题的最佳解决方案，但答案的格式符合我的喜好。对不起，我之前没有向您提供此更新。我的真实条件是，当NA是可选的时，ADD必须始终存在。除了强制的ADD和可选的NA之外，不能存在其他值。如果不存在预期的NA，则上述条件将返回true。如果NA是可选的，则u只能有“添加”的条件。如果String.containsadd{return false；}我的意思是{ADD，NA}可以是true，{ADD}可以是true，但是{ADD，DEL}或{ADD，YAK}或{DEL，YAK}将是false。不仅ADD必须始终存在，但是，除NA之外的任何其他值以及ADD都应返回false。我的真实条件是，当NA为可选时，ADD必须始终存在。除强制ADD和可选NA之外，不得存在其他值。如果没有预期的NA，则上述条件将返回true。我的真实条件是，当NA为可选时，ADD必须始终存在。除强制ADD和可选NA外，不得存在其他值。请更新我们如何在您的解决方案中添加此检查？只需添加条件setToCheck.containsADD@不幸的是，如果所有操作只包含ADD，则此条件将返回false。还有| | |！actions.containsNA&&actions.size==1将在allActions包含其他值（如DEL）时返回true。这个逻辑有很多问题，我测试过了。它起作用了。我的解决方案检查它是否包含ADD，如果hashset包含NA，那么它的大小必须是2，否则大小将是1。很抱歉，在我将其粘贴到IDE中进行测试后，我错误地删除了括号并将其放错了位置。这很有效，谢谢。
import java.util.HashSet;
import java.util.Set;
public class HashSetTheory {
public static void main(String args[]){
String[] sourceData = {"ADD","DEL","CHG","DEL","NA","ADD","BLAH","YAK" }; // Output is false
//String[] sourceData = {"ADD","ADD","ADD","NA","NA","ADD","NA","ADD" }; // Output is true
//String[] sourceData = {"ADD","ADD","ADD" }; // Output is true
//String[] sourceData = { }; // Output is false
//String[] sourceData = { "NA" , "Something"}; // Output is false
Set<String> myRepo = new HashSet<>();
// Populating the set with input data
for(String data : sourceData){
myRepo.add(data);
}
Set<String> check = new HashSet<>();
check.add("NA");
check.add("ADD");
System.out.println("==>" + validateData(myRepo,check) );
}
public static boolean validateData(Set<String> myRepo,Set<String> check){
boolean retVal = true;
if(myRepo.size()==0){
return false;
}
for (String s : myRepo) {
// Adding an element in set returns false if it already exists
if(check.add(s)){
//This check is pass only if the set has some new item in it
retVal = false;
break;
}
}
return retVal;
}
}