我目前正在使用此選項3：下載統計信息來處理C語言如果用戶選擇此選項，程序將使用以下數據創建統計文件：a. Power output sorted from lowest to highest
b. Day with highest output
c. Total by month
d. Average power output for all the data統計信息文件將與輸入文件具有相同的名稱，但附加了_stats.txt。例如，如果輸入文件名為data.txt，則stats文件將命名為data_stats.txt。我的數據文件包含January 10 2018 236.9January 11 2018 267.6January 12 2018 278.1January 13 2018 246.9January 14 2018 262.3January 15 2018 288.6February
2 2018 199.7February 3 2018 134.6February 4 2018 200.8February 5 2018 198.2March 9 2018 169.7March 10 2018 168.3March 11 2018 179.4當我運行C時，我的總功率是288.6，我如何獲得每個月的總和？ public static void createStatsFile(ArrayList<Entry> uploadResults) {
///////////////
///////A///////
///////////////
try {
PrintWriter writer = new PrintWriter("data_stat.txt", "UTF-8");
ArrayList<Entry> lowestToHighest = bubbleSort(uploadResults);
for(Entry entry : lowestToHighest) {
writer.print(
"Month: " + entry.getMonth() + " Day: " + entry.getDay() + " Year: " + entry.getYear() + " Power Output: "
+ entry.getPowerOutput());
writer.print("\n");
entry.print();
}我的課：public class Entry {
//declaring variables
private String month;
private String day;
private String year;
private float powerOutput;
private String file;
private int[] MonthList;
String inputFile = file;
//Constructors
public Entry() {
}
public Entry(String m, String d, String y, float p) {
month = m;
day = d;
year = y;
powerOutput = p;
}
//creating print to call ArrayList in main
public void print() {
System.out.println("Month: " + month + " Day: " + day + " Year: " + year + " Power Output: " + powerOutput);
}
public static void getFile() {
}
public String getMonth() {
return month;
}
2 回答
慕村9548890
TA貢獻1884條經驗 獲得超4個贊
您可以使用流來獲取所需結果的Map。
Map<String, Double> collect = uploadResults.stream().collect( Collectors.groupingBy(Entry::getMonth, Collectors.summingDouble(Entry::getPowerOutput)));
工作
List<Entry> uploadResults = Arrays.asList(
new Entry("January","10","2018",236.9f),
new Entry("January","11","2018",267.6f),
new Entry("January","12","2018",278.1f),
new Entry("January","13","2018",246.9f),
new Entry("January","14","2018",262.3f),
new Entry("January","15","2018",288.6f),
new Entry("February","2","2018",199.7f),
new Entry("February","3","2018",134.6f),
new Entry("February","4","2018",200.8f),
new Entry("February","5","2018",198.2f),
new Entry("March","9","2018",169.7f),
new Entry("March","10","2018",168.3f),
new Entry("March","11","2018",179.4f));Map<String, Double> collect = uploadResults.stream().collect(
Collectors.groupingBy(Entry::getMonth, Collectors.summingDouble(Entry::getPowerOutput)));System.out.println(collect);產量
{March=517.3999938964844, February=733.3000030517578, January=1580.3999938964844}編輯：
對于Java8以下的版本，應該這樣做
Map<String, Float> monthMap = new HashMap<>();for (Entry uploadResult : uploadResults) {
String month = uploadResult.getMonth();
Float powerOutput = uploadResult.getPowerOutput();
if( monthMap.containsKey(month) ){
powerOutput += monthMap.get(month);
}
monthMap.put( month, powerOutput);}System.out.println(monthMap);
繁星點點滴滴
TA貢獻1803條經驗 獲得超3個贊
在這里，您可以在每個循環中初始化總和。
Entry tempEntry = null;
for(Entry entry: uploadResults) {
float sum;
sum =entry.getPowerOutput();
}float sum;在總和之前移動并添加到總和：
Entry tempEntry = null;
float sum = 0;
for(Entry entry: uploadResults) {
sum += entry.getPowerOutput();
}添加回答
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