Java:在新行的开头匹配重复字符并替换相同数量的备选项

Question

我有一个带有多行的纯文本文件(新行字符是\n)这些行中的一些以不同数量的连续重复空白字符开头\\s.我想替换每个\\s用 .示例文件:

This is a line with no white space at the beginning
  This is a line with 2 whitespace characters at the beginning
    This is a line with 4 whitespace at the beginning

转换为:

This is a line with no white space at the beginning
  This is a line with two whitespace characters at the beginning
    This is a line with 4 whitespace at the beginning

有什么建议？

谢谢

Answer 1

text = text.replaceAll("(?m)(?:^|\\G) ", " ");

^在MULTILINE模式下匹配一行的开头.
\G匹配上一个匹配结束的位置(如果没有先前的匹配,则匹配输入的开头).

如果您一次处理一行,则可以将正则表达式缩短为"\\G ".