首先,我必须道歉,因为我不确定如何很好地说出我的头衔。
然而,我面临的问题是继续提出另一个问题,这使我更接近完成这个特定的计划。尽管如此。
这是我目前的输出:
Income
{Jack=46, Mike=52, Joe=191}
这些都在HashMap中,我打印出来,虽然我需要做的是使这个输出更具可见性,我想这导致需要从Map内部操作/获取某些数据,然后使其呈现。< / p>
我的目标是让我的输出看起来像这样:
Jack: $191
Mike: $52
Joe: $46
我对Java和编程一般都很陌生,所以我只是想知道这是否可能,或者我是否从一开始就以错误的方式处理了这一切?
以下是我的代码:
public static void main(String[] args) {
String name;
int leftNum, rightNum;
//Scan the text file
Scanner scan = new Scanner(Test3.class.getResourceAsStream("pay.txt"));
Map < String, Long > nameSumMap = new HashMap < > (3);
while (scan.hasNext()) { //finds next line
name = scan.next(); //find the name on the line
leftNum = scan.nextInt(); //get price
rightNum = scan.nextInt(); //get quantity
Long sum = nameSumMap.get(name);
if (sum == null) { // first time we see "name"
nameSumMap.put(name, Long.valueOf(leftNum + rightNum));
} else {
nameSumMap.put(name, sum + leftNum + rightNum);
}
}
System.out.println("Income");
System.out.println(nameSumMap); //print out names and total next to them
//output looks like this ---> {Jack=46, Mike=52, Joe=191}
//the next problem is how do I get those names on seperate lines
//and the total next to those names have the symbol $ next to them.
//Also is it possible to change = into :
//I need my output to look like below
/*
Jack: $191
Mike: $52
Joe: $46
*/
}
}
答案 0 :(得分:2)
好而不是依赖于toString()
的默认HashMap
实现,只需循环条目:
for (Map.Entry<String, Long> entry : nameSumMap.entrySet()) {
System.out.println(entry.getKey() + ": $" + entry.getValue());
}
答案 1 :(得分:0)
使用Iterator遍历Map并打印其所有内容,以下示例应该适合您。
Iterator iterator = nameSumMap.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry mapEntry = (Map.Entry) iterator.next();
System.out.println(mapEntry.getKey()
+ ": $" + mapEntry.getValue());
}