我已经使用ArrayList（java），aList1和aList2创建了两个数组。两者都将混合使用双打和弦乐。如何直接将aList1的个别内容与aList2中相应的个别内容进行比较。例如，如果aList1中的第一个值或字符串与第一个值不匹配或aList2中的字符串，应该有一条消息说两者不匹配。这应该在每个ArrayList的每个元素上继续。
谢谢！
编辑：
这是我最初的尝试：
if (!aList1.get(0).equals(aList2.get(0))) {
JOptionPane.showMessageDialog(null, "#1 is incorrect.");
}
if (!aList1.get(1).equals(aList2.get(1))) {
JOptionPane.showMessageDialog(null, "#2 is incorrect.");
}
依此类推，通过比较aList1和aList2中的每个元素，看看它们是否相等（无论它们是双精度型还是字符串）。相应的元素和数组的大小将始终相同。因此，例如，如果aList1 = {0,1,2,3,4，dog}，则aList2可以包含{10,2,5,2，cat}。
编辑：整个代码。
import javax.swing.JOptionPane;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.Writer;
import java.util.ArrayList;
public class KevinMath2 {
static File filename = new File("homework.txt");
static ArrayList <Object> aList = new ArrayList <Object> ();
static String homework = " ";
static File filename2 = new File("homework2.txt");
static ArrayList <Object> aList2 = new ArrayList <Object> ();
static String homework2 = " ";
public static void main(String[] args) {
// TODO Auto-generated method stub
String initialInput = JOptionPane.showInputDialog(null, "Would you like to add answers or check answers?");
String again;
char repeat;
do {
switch (initialInput) {
case "Add answers":
char answerfinal1;
String answerPass = JOptionPane.showInputDialog(null, "Please enter the password");
while (!answerPass.equals("Victor")) {
JOptionPane.showMessageDialog(null, "Incorrect Password. Please try again.");
answerPass = JOptionPane.showInputDialog(null, "Please enter the password.");
}
do {
do {
String options = JOptionPane.showInputDialog(null, "Enter the date of the desired" +
" answers to add (M/D/Y)");
switch (options) {
case "05/29/15":
while (!homework.isEmpty()) {
homework = JOptionPane.showInputDialog("Please enter the answers, in order. After "
+ "the last answer, leave the next answer"
+ " blank, and click OK.");
if (!homework.isEmpty()) aList.add(homework);
}
try {
FileWriter fw = new FileWriter (filename);
Writer output = new BufferedWriter (fw);
int sz = aList.size();
for (int i=0; i < sz; i++) {
output.write(aList.get(i).toString() + "\n");
}
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Oops! I cannot create that file.");
}
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid date.");
break;
}
} while (!homework.isEmpty());
String final1 = JOptionPane.showInputDialog(null, "Is this correct: " + aList.get(0) + " "
+ aList.get(1) + " " + aList.get(2) + " " +
aList.get(3) + " " + aList.get(4) + "? (Yes or No)");
answerfinal1 = final1.charAt(0);
} while (answerfinal1 == 'n' || answerfinal1 == 'N');
break;
//Need to store the array permanently
case "Check answers": //Need to make it so it stores array of Kevin's answers permanently
char answerfinal2;
String checkPass = JOptionPane.showInputDialog(null, "Please enter the password");
while (!checkPass.equals("Kevin")) {
JOptionPane.showMessageDialog(null, "Incorrect Password. Please try again.");
answerPass = JOptionPane.showInputDialog(null, "Please enter the password.");
}
do {
do {
String options2 = JOptionPane.showInputDialog(null, "Enter the date of the desired" +
" answers to check (M/D/Y)");
switch (options2) {
case "05/29/15":
while (!homework2.isEmpty()) {
homework2 = JOptionPane.showInputDialog("Please enter the answers, in order. After "
+ "the last answer, leave the next answer" +
" blank, and click OK.");
if (!homework2.isEmpty()) aList2.add(homework2);
}
try {
FileWriter fw = new FileWriter (filename2);
Writer output = new BufferedWriter (fw);
int sz = aList2.size();
for (int i=0; i < sz; i++) {
output.write(aList2.get(i).toString() + "\n");
}
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Oops! I cannot create that file.");
}
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid date.");
}
} while (!homework2.isEmpty());
String final2 = JOptionPane.showInputDialog(null, "Is this correct: " + aList2.get(0) + " "
+ aList2.get(1) + " " + aList2.get(2) + " " +
aList2.get(3) + " " + aList2.get(4) + "? (Yes or No)");
answerfinal2 = final2.charAt(0);
} while (answerfinal2 == 'n' || answerfinal2 == 'N');
int i = 0; // counter variable
if (aList.size() == aList2.size()) { // Check if both lists are equal
for (Object obj : aList) { // iterate through any list
if (obj.getClass() == String.class) { // find if it's a string
if (!aList.get(i).equals(aList2.get(i))) {
JOptionPane.showMessageDialog(null, "#" + i + " is wrong.");
}
}
if (obj.getClass() == Double.class) { // or a double
if (!aList.get(i).equals(aList2.get(i))) {
JOptionPane.showMessageDialog(null, "#" + i + " is wrong.");
}
}
i++;
}
}
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
break;
}
again = JOptionPane.showInputDialog(null, "Would you like to check another answer, or "+
"add another answer? (Yes or No)");
repeat = again.charAt(0);
} while (repeat == 'y' || repeat == 'Y');
JOptionPane.showMessageDialog(null, "Thanks for using this program");
}
}
答案 0 :(得分：2)
尝试使用for循环迭代第一个ArrayList并使用for循环中的计数器（以下示例中的＃）;来比较使用get方法循环的每个索引由ArrayList提供。
for (int i = 0; i < aList1.size(); i++) {
if (!aList1.get(i).equals(aList2.get(i)))
//output whatever you want it to say
}
编辑：更改为.equals而不是==作为建议。好抓。
答案 1 :(得分：0)
比较列表中两个元素的数据类型，如果它们匹配，则尝试比较它们的内容 要比较数据类型，请遵循以下提到的代码
int a = 10;
Object o = a;
System.out.println(o.getClass().getSimpleName());
如果数据类型匹配，则尝试比较其内容
答案 2 :(得分：0)
我同意coal175s的答案，但既然你说你在数组列表中混合了类型，你应该使用.equals（）方法来比较它们。
if !(aList1.get(i).equals(aList2.get(i))) {
答案 3 :(得分：0)
您应该使用List通用语Object初始化您的List<Object> list = new ArrayList<>();对象，以便在列表中添加String和Double。
这是比较两个阵列的理想解决方案。
List<Object> aList1 = new ArrayList<Object>();
List<Object> aList2 = new ArrayList<Object>();
aList1.add("abc");
aList1.add(25);
aList2.add("abc");
aList2.add(25);
int i = 0; // counter variable
if (aList1.size() == aList2.size()) { // Check if both lists are equal
for (Object obj : aList1) { // iterate through any list
if (obj.getClass() == String.class) { // find if it's a string
if (aList1.get(i).equals(aList2.get(i))) {
JOptionPane.showMessageDialog(null, (i+1) + " is correct.");
} else {
JOptionPane.showMessageDialog(null, (i+1) + " is incorrect.");
}
}
if (obj.getClass() == Double.class) { // or a double
if (aList1.get(i).equals(aList2.get(i))) {
JOptionPane.showMessageDialog(null, (i+1) + " is correct.");
} else {
JOptionPane.showMessageDialog(null, (i+1) + " is incorrect.");
}
}
if (obj.getClass() == Integer.class) {
JOptionPane.showMessageDialog(null, "Integer is found");
}
i++;
}
}
您的代码很难遵循，当您编写程序时，请尝试遵循Java惯例。
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.Writer;
import java.util.ArrayList;
import javax.swing.JOptionPane;
public class KevinMath2 {
static File filename = new File("homework.txt");
static ArrayList<Object> aList = new ArrayList<Object>();
static String homework = "";
static File filename2 = new File("homework2.txt");
static ArrayList<Object> aList2 = new ArrayList<Object>();
static String homework2 = "";
static String answerPass = "";
static final int TOTAL_QUESTIONS = 5;
public static void main(String[] args) {
String initialInput = JOptionPane.showInputDialog(null,
"Enter Add answers / Check answers to continue");
switch (initialInput) {
case "Add answers":
answers("Victor", aList, filename);
int choice = JOptionPane.showConfirmDialog(null,
"Would you like to compare your answers?", "Yes/No", JOptionPane.YES_NO_OPTION);
if (choice == JOptionPane.YES_OPTION) {
answers("Kevin", aList2, filename2);
checkAnswers(aList, aList2);
}
break;
// Need to store the array permanently
case "Check answers": // Need to make it so it stores array of
// Kevin's answers permanently
answers("Kevin", aList2, filename2);
if (aList.size() == 0) {
JOptionPane.showMessageDialog(null,
"Please add answers to compare.");
answers("Victor", aList, filename);
}
checkAnswers(aList, aList2);
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
break;
}
// exit the program
JOptionPane.showMessageDialog(null, "Thanks for using this program");
}
public static void answers(String pass, ArrayList<Object> list, File f) {
answerPass = JOptionPane.showInputDialog(null,
"Please enter the password");
// validate user
while (!answerPass.equals(pass)) {
JOptionPane.showMessageDialog(null,
"Incorrect Password. Please try again.");
answerPass = JOptionPane.showInputDialog(null,
"Please enter the password.");
}
// add answers
String final1 = "";
do {
clearFile(f);
list.clear();
// validate the date of the answers
String options = JOptionPane.showInputDialog(null,
"Enter the date of the desired" + " answers (MM/DD/YY)");
// add your answers
enterAnswers(options, list, f);
// verify the answers
final1 = JOptionPane.showInputDialog(null, "Is this correct: "
+ list.get(0) + " " + list.get(1) + " " + list.get(2) + " "
+ list.get(3) + " " + list.get(4) + "? (Y/N)");
} while (final1.charAt(0) == 'n' || final1.charAt(0) == 'N');
}
public static void enterAnswers(String options, ArrayList<Object> list,
File f) {
switch (options) {
case "05/29/15":
boolean valid = false;
for (int i = 0; i < 5; i++) {
while (!valid) {
homework = JOptionPane
.showInputDialog("Please enter your answer for question "
+ (i + 1));
if (!homework.isEmpty())
valid = true;
}
list.add(homework);
valid = false;
}
writeFile(f, list); // write the answers to a file
break;
default:
JOptionPane.showMessageDialog(null, "Please enter a valid date.");
}
}
public static void writeFile(File filename, ArrayList<Object> list) {
try {
FileWriter fw = new FileWriter(filename);
Writer output = new BufferedWriter(fw);
for (int j = 0; j < list.size(); j++) {
output.write(list.get(j) + "\n");
}
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null,
"Oops! I cannot create that file.");
}
}
public static void clearFile(File filename) {
try {
FileWriter fw = new FileWriter(filename);
Writer output = new BufferedWriter(fw);
output.write("");
output.close();
} catch (Exception e) {
JOptionPane.showMessageDialog(null,
"Oops! I cannot create that file.");
}
}
public static void checkAnswers(ArrayList<Object> a, ArrayList<Object> b) {
int i = 0; // counter variable
if (a.size() == b.size()) { // Check if both lists are
// equal
for (Object obj : a) { // iterate through any list
if (obj.getClass() == String.class) { // find if it's a
// string
if (!a.get(i).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + i
+ " is wrong.");
}
}
if (obj.getClass() == Double.class) { // or a double
if (!a.get(i).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + i
+ " is wrong.");
}
}
if (obj.getClass() == Integer.class) { // or an integer
if (!a.get(i).equals(b.get(i))) {
JOptionPane.showMessageDialog(null, "#" + i
+ " is wrong.");
}
}
i++;
}
}
}
}
答案基于假设
您正在撰写已添加的答案＆＃39;到某个文件，但您不会再次阅读该文件，以便与您的“检查答案”进行比较。要做到这一点，请编写另一种方法来阅读homework.txt文件，将每一行存储到aList，然后与aList2进行比较。
答案 4 :(得分：0)
需要考虑两件事：
说完了：
java.lang.Integer: 1234 != java.lang.String: 1234
999 != 9991
结果（来自list1的999.999未被检查）：
$ docker