读取C中的.txt文件时出现问题#从(立即清空整行之后)到(下一个空整行之后)

尝试以下操作:

        public static string[] GetRandomParagraph(string filePath)
        {
            if (File.Exists(filePath))
            {
                string text = File.ReadAllText(filePath);
                string[] paragraphs = text.Split(new string[] { "\n\n" }, StringSplitOptions.None);
                return paragraphs[new Random().Next(0, paragraphs.Length)].Split('\n');

            }
            else
                throw new FileNotFoundException("The file was not found", filePath);
        }

我真的希望这就是你想要的。

// This builds a list of Paragraph first
public static List<string> GetParagraphs(string filename)
{        
    var paragraphs = new List<string>();
    var lines = File.ReadAllLines(filename);
    bool newParagraph = true;
    string CurrentParagraph = string.Empty;
    // Build the list of paragraphs by adding to the currentParagraph until empty lines and then starting a new one
    foreach(var line in lines)
    {
        if(newParagraph)
        {
            CurrentParagraph = line;
            newParagraph = false;
        }
        else
        {
            if(string.IsNullOrWhiteSpace(line))// we're starting a new paragraph, add it to the list of paragraphs and reset current paragraph for next one
            {
                paragraphs.Add(CurrentParagraph);
                CurrentParagraph = string.Empty;
                newParagraph = true;
            }
            else // we're still in the same paragraph, add the line to current paragraph
            {
                newParagraph += (Environment.NewLine + line);
            }
        }
    }
    // Careful, if your file doesn't end with a newline the last paragraph won't count as one, in that case add it manually here.
}

public static Random rnd = new Random();

// And this returns a random one
public static string GetRandomParagraph(string fileName)
{
     var allParagraphs = GetParagraphs(filename);
     allParagraphs[rnd.Next(0,allParagraphs.length-1)]; // pick one of the paragraphs at random, stop at length-1 as collection indexers are 0 based    
}

试试这个:

public static string GetRandomLine(string filename)
    {
        var lines = File.ReadAllLines(filename);
        var lineNumber = _rand.Next(0, lines.Length - 1);
        var blankBefore = lineNumber;
        var blankAfter = lineNumber + 1;
        string reply = "";

        while (lines[blankBefore].Length > 0)
        {
            blankBefore--;
        }

        while (lines[blankAfter].Length != 0)
        {
            blankAfter++;
        }

        for ( int i = blankBefore + 1; blankBefore < blankAfter; blankBefore++)
        {
            reply += lines[i];
        }
        return reply;
    }

根据您的描述,我假设文件以一个空白行开头和结尾。通过将随机行的独占上限设置为比行长度小1,可以避免随机行成为文件的最后一行。如果随机行是一个空行,blankBefore将是该行的索引,否则,它将被回溯到它到达上一个空白行。blankAfter从随机行之后的下一行的索引开始,如果该行不是空的,blankAfter将增加,直到它成为下一个空行的索引。

一旦你在目标段落之前和之后都有空白行的索引,只需在它们之间附加行来回答。

如果文件的第一行和最后一行不为空,则需要验证blankBefore和blankAfter是否仍在数组的边界内。

我对上面由@TheCoderCrab提供的代码做了一些修改。我把这个方法变成了一个字符串方法,这样它就会返回一个字符串。我只是简单地添加了一个for循环,将段落数组的所有字符追加到一个新字符串上,这个字符串将返回main。非常感谢。

public static string GetRandomParagraph(string filePath)
    {
        if (File.Exists(filePath))
        {
            string text = File.ReadAllText(filePath);
            string[] paragraphs = text.Split(new string[] { "\n\n" }, StringSplitOptions.None);
            string [] paragraph = paragraphs[new Random().Next(0, paragraphs.Length)].Split('\n');

            //Added a for loop to build the string out of all the characters in the 'paragraph' array index.
            string pReturn = "";
            for (int a = 0; a < paragraph.Length; a++)
            {
                //Loop through and consecutively append each character of mapped array index to a return string 'pReturn'
                pReturn = pReturn + paragraph[a].ToString();
            }

            return pReturn;

        }
        else
            throw new FileNotFoundException("The file was not found", filePath);
    }

得到完整的段落

public static string GetRandomParagraph(string fileName)
{
    /* 
       Rather than reading all the lines, read all the text
       this gives you the ability to split by paragraph
    */
    var allText = File.ReadAllText(fileName);
    // Use as separator for paragraphs
    var paragraphSeparator = $"{Environment.NewLine}{Environment.NewLine}";
    // Treat large white spaces after a new line as separate paragraphs 
    allText = Regex.Replace(allText, @"(\n\s{3,})", paragraphSeparator);
    // Split the text into paragraphs
    var paragraphs = allText.Split(paragraphSeparator);
    // Get a random index between 0 and the amount of paragraphs
    var randomParagraph = new Random().Next(0, paragraphs.Length);

    return paragraphs[randomParagraph];
}