[英]How do I sort this array list in java
我正在使用OpenCsv访问要排序的文件,然后写回另一个文件名。 排序列表时遇到问题。 谢谢。
我正在尝试按第一列和第二列对csv文件进行排序。
CSVReader reader = new CSVReader(new FileReader("d:\\temp\\data1.csv"), ',', '"', 1);
//Read all rows at once
List<String[]> allRows = reader.readAll();
//Read CSV line by line and use the string array as you want
for(String[] row : allRows){
System.out.println(Arrays.toString(row));
}
*Arrays.sort(allRows.toArray());*
CSVWriter writer = new CSVWriter(new FileWriter("d:\\temp\\data1sorted.csv"));
writer.writeAll(allRows);
//close the writer
writer.close();
运行此代码时出现以下错误:
Exception in thread "main" java.lang.ClassCastException: [Ljava.lang.String; cannot be cast to java.lang.Comparable
at java.util.ComparableTimSort.countRunAndMakeAscending(Unknown Source)
at java.util.ComparableTimSort.sort(Unknown Source)
at java.util.ComparableTimSort.sort(Unknown Source)
at java.util.Arrays.sort(Unknown Source)
at CompareCsv.main(CompareCsv.java:31)
这对您有帮助吗?
public static void main(String args[]) {
ArrayList<String> animalList = new ArrayList<String>();
animalList.add("Dog");
animalList.add("Cat");
animalList.add("Snake");
animalList.add("Bison");
System.out.println("Before Sorting:");
for (String tmpStr : animalList) {
System.out.println(tmpStr);
}
// sorting
Collections.sort(animalList);
System.out.println("After Sorting:");
for (String tmpStr : animalList) {
System.out.println(tmpStr);
}
}
目前尚不清楚是要对行进行排序还是将它们进行比较。 兼而有之;
for(String[] row : allRows)
{
Arrays.sort(row);
}
Collections.sort(allRows, new Comparator()
{
@Override
public int compare(Object o1, Object o2)
{
String[] a = (String[])o1;
String[] b = (String[])o2;
return a[0].compareTo(b[0]); //you'll probably want some additional checking here.
}
});
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.