删除java字符串中选定的新行并维护字符串顺序[关闭]答案

【问题标题】：Remove selected new line in java string and maintain the String order [closed]删除java字符串中选定的新行并维护字符串顺序[关闭]
【发布时间】：2020-12-03 03:37:07
【问题描述】：

我想从给定的字符串格式中删除新行

     This is test;
 
 
 
 This is new test;
 
 
 
 
 This is new test2;
 
 This is another string test;
 
 
 
 
 
 
 
 
 this is more space string test;

输出应该是这样的：

 This is test;
 This is new test;
 This is new test2;
 This is another string test;
 this is more space string test;

我知道我可以使用正则表达式或全部替换为“\n” 但在这种情况下，所有字符串都将被替换为单行，并且我想要的字符串顺序不会被维护。？

【问题讨论】：

我发布这个问题是为了避免暴力破解，因为我的实际文件为 1 MB，如果有任何具体方法，我需要知道

标签： java string replace removing-whitespace

【解决方案1】：

一种选择是在点全模式下对以下模式进行正则表达式替换：

\r?\n\s*

然后，只需用换行符替换，即可保留原来的单个换行符。

String input = "Line 1\r\n\n\n\n     Line 2 blah blah blah\r\n\r\n\n   Line 3 the end.";
System.out.println("Before:\n" + input + "\n");
input = input.replaceAll("(?s)\r?\n\\s*", "\n");
System.out.println("After:\n" + input);

打印出来：

Before:
Line 1



 Line 2 blah blah blah


   Line 3 the end.

After:
Line 1
Line 2 blah blah blah
Line 3 the end.

【讨论】：

谢谢蒂姆，它对我有用 :)

【解决方案2】：

Project structure

input.txt

       This is test;



 This is new test;




 This is new test2;

 This is another string test;








 this is more space string test;

Main.class

public class Main {
   private static String input = "";
   public static void main(String[] args) throws IOException {
       //Reading the file, taking into account all spaces and margins.
        Files.lines(Paths.get("src/input.txt"), StandardCharsets.UTF_8).forEach(e->{
           input = input.concat(e);
           input = input.concat("\n");
        });

        while (input.contains("\n\n")){
            input = input.replace("\n\n","\n");
        }
        //trim the margins on both sides
        input = input.trim();
        System.out.println(input);
    }
}

结果

This is test;
This is new test;
This is new test2;
This is another string test;
this is more space string test;

【讨论】：

【解决方案3】：

试试这个。

String text = Files.lines(Paths.get("input.txt"))
    .map(line -> line.trim())
    .filter(line -> !line.isEmpty())
    .collect(Collectors.joining("\n"));
System.out.println(text);

输出

This is test;
This is new test;
This is new test2;
This is another string test;
this is more space string test;

【讨论】：