我有一项任务，我必须按照“负担得起的医疗保健法”注册的符合条件的公民的最低百分比排列美国各州。我不得不创建一个ArrayList，它拥有两种不同类型的数据：两个字符串和三个双精度数据。我已经接近完成但是我被困在了：
如何逐行打印状态？我想我应该使用t /开始新的一行。
如何按从高到低的百分比顺序打印状态？
到目前为止代码。
import java.util.*;
import java.io.*;
import java.util.ArrayList;
// Calculates the percentage of citizens enrolled in the Affordable Healthcare Act
// Lists the states in order of highest percentage of enrolled citizens in the Affordable Healthcare Act
public class ACA {
public static void main( String[] args ) throws FileNotFoundException {
Scanner keyboard = new Scanner(System.in); // creates an object of the Scanner class
System.out.println("Enter filename"); // prompts the user for the name of the file
String filename = keyboard.next(); // the user response is stored
File inputFile = new File(filename+".txt"); // takes the filename and creates an object of the File class
Scanner fileIn = new Scanner(inputFile); // takes the object and converts the file to an obect of the Scanner class to allow it to be read
// creates an object of the ArrayList class
ArrayList<ACAdata> info = new ArrayList<>();
// variables declared for each column of data in the line
String state = " "; // State abbreviation
String org = " "; // Organizer of the ACA marketplace, either FFM for federally facilitated marketplace or SBM for state based marketplace.
double numEll = 0; // Number of citizens in the state eligible for ACA coverage
double numEn = 0; // Number of citizens who enrolled in an ACA plan
// while loop will evaluate as long as there are rows of data in the text file
while ( fileIn.hasNext() ) {
state = fileIn.next(); // individual state
org = fileIn.next(); // organization
numEll = fileIn.nextDouble(); // number of elligible citizens for that state for the Affordable Healthcare Act
numEn = fileIn.nextDouble(); // number of citizens enrolled in the Affordable Healthcare Act
double percentage = per( numEll, numEn ); // calls the per method to calculate a percentage for each state
// adds the 5 fields of data to a new ArrayList that holds the information for each state
info.add(new ACAdata( state, org, numEll, numEn, percentage));
}
// Prints out the information about the state
for ( int i = 0; i < info.size(); i++ ) {
System.out.println((info.get(i)).toString());
}
}
// method that finds the percentage of enrolled citizens that are elligible for the Affordable Care Act
public static double per( double Ell, double En ) {
double calculation = En / Ell * 100; // divides the Enrolled by the number of elligible citizens
return calculation; // returns the calculation
}
}
public class ACAdata {
// variables declared for each column of data in the line
String state = " "; // State abbreviation
String org = " "; // Organizer of the ACA marketplace, either FFM for federally facilitated marketplace or SBM for state based marketplace.
double numEll = 0; // Number of citizens in the state eligible for ACA coverage
double numEn = 0; // Number of citizens who enrolled in an ACA plan
double percentage = 0;
public ACAdata ( String state, String org, double numEll, double numEn, double percentage ) {
state = state;
org = org;
numEll = numEll;
numEn = numEn;
percentage = percentage;
}
public String getState() {
return this.state;
}
public void setState(String state) {
this.state = state;
}
public String getOrg() {
return this.org;
}
public void setOrg( String org ) {
this.org = org;
}
public double getNumEll() {
return this.numEll;
}
public void setNumEll( double numEll ) {
this.numEll = numEll;
}
public double getNumEn( double numEn ) {
return this.numEn;
}
public double getPercentage() {
return this.percentage;
}
public void setPercentage( double percentage ) {
this.percentage = percentage;
}
}
答案 0 :(得分：1)
使ACAdata对象可排序。 如果你有这个对象，你可以对它进行排序，然后用。
输出ArrayList<ACAdata> list = new ArrayList<>();
Collections.sort(list);
for (Iterator<ACAdata> iterator = list.iterator(); iterator.hasNext();) {
ACAdata next = iterator.next();
System.out.println(next.toString());
}
public class ACAdata implements Comparable<ACAdata> {
// variables declared for each column of data in the line
String state = " "; // State abbreviation
String org = " "; // Organizer of the ACA marketplace, either FFM for federally facilitated marketplace or SBM for state based marketplace.
double numEll = 0; // Number of citizens in the state eligible for ACA coverage
double numEn = 0; // Number of citizens who enrolled in an ACA plan
double percentage = 0;
public ACAdata(String state, String org, double numEll, double numEn, double percentage) {
state = state;
org = org;
numEll = numEll;
numEn = numEn;
percentage = percentage;
}
public String getState() {
return this.state;
}
public void setState(String state) {
this.state = state;
}
public String getOrg() {
return this.org;
}
public void setOrg(String org) {
this.org = org;
}
public double getNumEll() {
return this.numEll;
}
public void setNumEll(double numEll) {
this.numEll = numEll;
}
public double getNumEn(double numEn) {
return this.numEn;
}
public double getPercentage() {
return this.percentage;
}
public void setPercentage(double percentage) {
this.percentage = percentage;
}
@Override
public int compareTo(ACAdata o) {
if (percentage > o.percentage) {
return -1;
}
if (percentage < o.percentage) {
return 1;
}
return 0;
}
@Override
public String toString() {
return "Put the info you want here!";
}
}
答案 1 :(得分：0)
查看您的代码，最简单的解决方案（我能想到的）是覆盖toString中的ACAdata，例如（按照您的需要添加和格式化）
@Override
public String toString() {
return String.format("%s %s %.2f %.2f", state, org, numEll, numEn);
}
然后您可以打印整个ArrayList或单个ACAdata实例。您已经拨打toString()了，但是您不必...当您尝试打印toString()时，Java会隐式地为您拨打Object电话（ Object中的默认实现只是没有做你想做的事。）