我有两个数组列表,如下所示,
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.*;
class Reader {
public static void main(String args[]) throws FileNotFoundException {
ArrayList<String> animal = new ArrayList<>();
animal.add("Dog");
animal.add("Cat");
animal.add("Mouse");
ArrayList<Integer> numbers = new ArrayList<>();
for (int i = 1; i <= 15; i++) {
numbers.add(i);
}
PrintWriter writer = new PrintWriter("animals.csv");
for (String ani : animal) {
writer.println(ani + ",");
}
writer.close();
}
}
我希望输出在.csv文件中是这样的。
Dog,1,2,3,4,5,
Cat,6,7,8,9,10,
Mouse,11,12,13,14,15,
当我使用for循环时,数组列表的输出会在.csv文件中一个接一个地打印出来。
答案 0 :(得分:1)
使用writer.print()
代替writer.println()
注意&#39; ln&#39;在您使用的方法名称中,这意味着打印行。
更新:还要添加数字和动物:
public static void main(final String[] args) throws FileNotFoundException {
ArrayList<String> animal = new ArrayList<>();
animal.add("Dog");
animal.add("Cat");
animal.add("Mouse");
ArrayList<Integer> numbers = new ArrayList<>();
for (int i = 1; i <= 15; i++) {
numbers.add(i);
}
PrintWriter writer = new PrintWriter("animals.csv");
List<String> row = new ArrayList<>();
int i = 0;
for (String ani : animal) {
row.add(ani);
for (int j = 0; j < 5; j++) {
row.add(String.valueOf(numbers.get(i++)));
}
writer.println(String.join(",", row));
row.clear();
}
writer.close();
}
答案 1 :(得分:0)
您的编写方法正在打印一行。你只需要使用打印。
因此writer.println(ani + ",");
变为writer.print(ani + ",");
此外,要按照您的要求添加数字,您可以将其作为替代方案。这就像你说动物名后每行只有5个元素一样。
PrintWriter writer = new PrintWriter("animals.csv");
int rowCounter = 0;
for (String ani : animals) {
writer.print(ani);
for (int i = rowCounter * 5; i < (rowCounter * 5 + 5); i++) {
writer.print("," + numbers.get(i));
}
writer.println();
rowCounter++;
}
writer.close();