如何读取仅由 LF 分隔的文件中的每一行？

发布于 2024-07-27 17:18:50 字数 849 浏览 6 评论 0 原文

我必须逐行读取日志文件。大小约为 6MB，总共 40000 行。但在测试我的程序后，我发现该日志文件仅由 LF 字符分隔。所以我无法使用StreamReader类的Readline方法

如何解决这个问题？

编辑：我尝试使用文本阅读器，但我的程序仍然无法工作：

using (TextReader sr = new StreamReader(strPath, Encoding.Unicode))
            {


                sr.ReadLine(); //ignore three first lines of log file
                sr.ReadLine(); 
                sr.ReadLine();

                int count = 0; //number of read line
                string strLine;
                while (sr.Peek()!=0)
                {
                    strLine = sr.ReadLine();
                    if (strLine.Trim() != "")
                    {
                        InsertData(strLine);
                        count++;
                    }
                }

                return count;
            }

原文

I have to read line-by-line a log file. It's about 6MB in size and 40000 line total. But after testing my program, I discover that that log file is only delimited by LF character only. So I can't use the Readline method of StreamReader class

How can I fix this problem?

edit: I tried to use Text Reader, but my program still didn't work:

using (TextReader sr = new StreamReader(strPath, Encoding.Unicode))
            {


                sr.ReadLine(); //ignore three first lines of log file
                sr.ReadLine(); 
                sr.ReadLine();

                int count = 0; //number of read line
                string strLine;
                while (sr.Peek()!=0)
                {
                    strLine = sr.ReadLine();
                    if (strLine.Trim() != "")
                    {
                        InsertData(strLine);
                        count++;
                    }
                }

                return count;
            }

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荒路情人 2024-08-03 17:18:51

TextReader.ReadLine 已经处理仅由 \n 终止的行。

来自文档：

一行被定义为一系列
字符后跟一个回车符
返回（0x000d），换行（0x000a），
回车符后跟一行
feed、Environment.NewLine 或 end
流标记。字符串是
返回的内容不包含
终止回车和/或
换行。返回值是一个
空引用（视觉上没有任何内容）
基本）如果输入流结束
已达到。

所以基本上，你应该没问题。它仍然可以与 StreamReader 一起使用。）

（我讨论的是 TextReader 而不是 StreamReader，因为那是声明该方法的地方 -显然如果您想轻松地遍历行（并且可能对日志文件使用 LINQ），您可以在 MiscUtil 很有用。它基本上将对 ReadLine() 的调用包装在迭代器中。例如，您可以执行以下操作：

var query = from file in Directory.GetFiles("logs")
            from line in new LineReader(file)
            where !line.StartsWith("DEBUG")
            select line;

foreach (string line in query)
{
    // ...
}

所有流式传输:)

TextReader.ReadLine already handles lines terminated just by \n.

From the docs:

A line is defined as a sequence of
characters followed by a carriage
return (0x000d), a line feed (0x000a),
a carriage return followed by a line
feed, Environment.NewLine, or the end
of stream marker. The string that is
returned does not contain the
terminating carriage return and/or
line feed. The returned value is a
null reference (Nothing in Visual
Basic) if the end of the input stream
has been reached.

So basically, you should be fine. (I've talked about TextReader rather than StreamReader because that's where the method is declared - obviously it will still work with a StreamReader.)

If you want to iterate through lines easily (and potentially use LINQ against the log file) you may find my LineReader class in MiscUtil useful. It basically wraps calls to ReadLine() in an iterator. So for instance, you can do:

var query = from file in Directory.GetFiles("logs")
            from line in new LineReader(file)
            where !line.StartsWith("DEBUG")
            select line;

foreach (string line in query)
{
    // ...
}

All streaming :)

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