我正在读取*.csv文件。

*.csv-file由分号(";")分隔的两列组成。

我能够阅读*.csv文件使用StreamReader,并能够通过使用Split()函数分离每一行。我想将每一列存储到一个单独的数组中,然后显示它。

有可能做到吗?


当前回答

var firstColumn = new List<string>();
var lastColumn = new List<string>();

// your code for reading CSV file

foreach(var line in file)
{
    var array = line.Split(';');
    firstColumn.Add(array[0]);
    lastColumn.Add(array[1]);
}

var firstArray = firstColumn.ToArray();
var lastArray = lastColumn.ToArray();

其他回答

仍然是错误的。你需要对引号中的""进行补偿。 这是我的解决方案微软风格csv。

               /// <summary>
    /// Microsoft style csv file.  " is the quote character, "" is an escaped quote.
    /// </summary>
    /// <param name="fileName"></param>
    /// <param name="sepChar"></param>
    /// <param name="quoteChar"></param>
    /// <param name="escChar"></param>
    /// <returns></returns>
    public static List<string[]> ReadCSVFileMSStyle(string fileName, char sepChar = ',', char quoteChar = '"')
    {
        List<string[]> ret = new List<string[]>();

        string[] csvRows = System.IO.File.ReadAllLines(fileName);

        foreach (string csvRow in csvRows)
        {
            bool inQuotes = false;
            List<string> fields = new List<string>();
            string field = "";
            for (int i = 0; i < csvRow.Length; i++)
            {
                if (inQuotes)
                {
                    // Is it a "" inside quoted area? (escaped litteral quote)
                    if(i < csvRow.Length - 1 && csvRow[i] == quoteChar && csvRow[i+1] == quoteChar)
                    {
                        i++;
                        field += quoteChar;
                    }
                    else if(csvRow[i] == quoteChar)
                    {
                        inQuotes = false;
                    }
                    else
                    {
                        field += csvRow[i];
                    }
                }
                else // Not in quoted region
                {
                     if (csvRow[i] == quoteChar)
                    {
                        inQuotes = true;
                    }
                    if (csvRow[i] == sepChar)
                    {
                        fields.Add(field);
                        field = "";
                    }
                    else 
                    {
                        field += csvRow[i];
                    }
                }
            }
            if (!string.IsNullOrEmpty(field))
            {
                fields.Add(field);
                field = "";
            }
            ret.Add(fields.ToArray());
        }

        return ret;
    }
}

这是我的2个简单的静态方法,将文本从csv文件转换为列表<列表<字符串>>,反之亦然。每种方法都使用行转换器。

这段代码应该考虑csv文件的所有可能性。您可以定义自己的csv分隔符,该方法尝试纠正转义双引号字符,并处理当所有文本在引号中是一个单元格,csv分隔符在引号字符串中,包括一个单元格中的多行,可以忽略空行。

最后一种方法仅用于测试。所以你可以忽略它,或者用这个测试方法测试你自己的或别人的解决方案:)。为了测试,我使用了这个硬csv, 4行2行:

0,a,""bc,d
"e, f",g,"this,is, o
ne ""lo
ng, cell""",h

这是最终代码。为了简单起见,我删除了所有的try catch块。

using System;
using System.Collections.Generic;
using System.Linq;

public static class Csv {
  public static string FromListToString(List<List<string>> csv, string separator = ",", char quotation = '"', bool returnFirstRow = true)
  {
    string content = "";
    for (int row = 0; row < csv.Count; row++) {
      content += (row > 0 ? Environment.NewLine : "") + RowFromListToString(csv[row], separator, quotation);
    }
    return content;
  }

  public static List<List<string>> FromStringToList(string content, string separator = ",", char quotation = '"', bool returnFirstRow = true, bool ignoreEmptyRows = true)
  {
    List<List<string>> csv = new List<List<string>>();
    string[] rows = content.Split(new string[] { Environment.NewLine }, StringSplitOptions.None);
    if (rows.Length <= (returnFirstRow ? 0 : 1)) { return csv; }
    List<string> csvRow = null;
    for (int rowIndex = 0; rowIndex < rows.Length; rowIndex++) {
      (List<string> row, bool rowClosed) = RowFromStringToList(rows[rowIndex], csvRow, separator, quotation);
      if (rowClosed) { if (!ignoreEmptyRows || row.Any(rowItem => rowItem.Length > 0)) { csv.Add(row); csvRow = null; } } // row ok, add to list
      else { csvRow = row; } // not fully created, continue
    }
    if (!returnFirstRow) { csv.RemoveAt(0); } // remove header
    return csv;
  }

  public static string RowFromListToString(List<string> csvData, string separator = ",", char quotation = '"')
  {
    csvData = csvData.Select(element =>
    {
      if (element.Contains(quotation)) {
        element = element.Replace(quotation.ToString(), quotation.ToString() + quotation.ToString());
      }
      if (element.Contains(separator) || element.Contains(Environment.NewLine)) {
        element = "\"" + element + "\"";
      }
      return element;
    }).ToList();
    return string.Join(separator, csvData);
  }

  public static (List<string>, bool) RowFromStringToList(string csvRow, List<string> continueWithRow = null, string separator = ",", char quotation = '"')
  {
    bool rowClosed = true;
    if (continueWithRow != null && continueWithRow.Count > 0) {
      // in previous result quotation are fixed so i need convert back to double quotation
      string previousCell = quotation.ToString() + continueWithRow.Last().Replace(quotation.ToString(), quotation.ToString() + quotation.ToString()) + Environment.NewLine;
      continueWithRow.RemoveAt(continueWithRow.Count - 1);
      csvRow = previousCell + csvRow;
    }

    char tempQuote = (char)162;
    while (csvRow.Contains(tempQuote)) { tempQuote = (char)(tempQuote + 1); }
    char tempSeparator = (char)(tempQuote + 1);
    while (csvRow.Contains(tempSeparator)) { tempSeparator = (char)(tempSeparator + 1); }

    csvRow = csvRow.Replace(quotation.ToString() + quotation.ToString(), tempQuote.ToString());
    if(csvRow.Split(new char[] { quotation }, StringSplitOptions.None).Length % 2 == 0) { rowClosed = !rowClosed; }
    string[] csvSplit = csvRow.Split(new string[] { separator }, StringSplitOptions.None);

    List<string> csvList = csvSplit
      .ToList()
      .Aggregate("",
          (string row, string item) => {
              if (row.Count((ch) => ch == quotation) % 2 == 0) { return row + (row.Length > 0 ? tempSeparator.ToString() : "") + item; }
              else { return row + separator + item; }
          },
          (string row) => row.Split(tempSeparator).Select((string item) => item.Trim(quotation).Replace(tempQuote, quotation))
      ).ToList();
    if (continueWithRow != null && continueWithRow.Count > 0) {
      return (continueWithRow.Concat(csvList).ToList(), rowClosed);
    }
    return (csvList, rowClosed);
  }

  public static bool Test()
  {
    string csvText = "0,a,\"\"bc,d" + Environment.NewLine + "\"e, f\",g,\"this,is, o" + Environment.NewLine + "ne \"\"lo" + Environment.NewLine + "ng, cell\"\"\",h";
    List<List<string>> csvList = new List<List<string>>() { new List<string>() { "0", "a", "\"bc", "d" }, new List<string>() { "e, f", "g", "this,is, o" + Environment.NewLine + "ne \"lo" + Environment.NewLine + "ng, cell\"", "h" } };

    List<List<string>> csvTextAsList = Csv.FromStringToList(csvText);
    bool ok = Enumerable.SequenceEqual(csvList[0], csvTextAsList[0]) && Enumerable.SequenceEqual(csvList[1], csvTextAsList[1]);
    string csvListAsText = Csv.FromListToString(csvList);
    return ok && csvListAsText == csvText;
  }
}

使用例子:

// get List<List<string>> representation of csv
var csvFromText = Csv.FromStringToList(csvAsText);

// read csv file with custom separator and quote
// return no header and ignore empty rows
var csvFile = File.ReadAllText(csvFileFullPath);
var csvFromFile = Csv.FromStringToList(csvFile, ";", '"', false, false);

// get text representation of csvData from List<List<string>>
var csvAsText = Csv.FromListToString(csvData);

注: 这:char tempQuote = (char)162;是ASCI表中的第一个稀有字符。脚本会搜索这个字符,或者不是文本中的第一个接下来的几个ascii字符,并将其用作临时转义和引用字符。

您不能立即创建数组,因为您需要从一开始就知道行数(这将需要读取csv文件两次)。

您可以将值存储在两个List<T>中,然后使用它们或使用List<T>.ToArray()将它们转换为数组

非常简单的例子:

var column1 = new List<string>();
var column2 = new List<string>();
using (var rd = new StreamReader("filename.csv"))
{
    while (!rd.EndOfStream)
    {
        var splits = rd.ReadLine().Split(';');
        column1.Add(splits[0]);
        column2.Add(splits[1]);
    }
}
// print column1
Console.WriteLine("Column 1:");
foreach (var element in column1)
    Console.WriteLine(element);

// print column2
Console.WriteLine("Column 2:");
foreach (var element in column2)
    Console.WriteLine(element);

N.B.

请注意,这只是一个非常简单的例子。使用字符串。Split不考虑某些记录包含分隔符的情况;在里面。 为了更安全的方法,可以考虑使用一些特定于csv的库,比如nuget上的CsvHelper。

如果你需要跳过(头部)行和/或列,你可以使用它来创建一个2维数组:

    var lines = File.ReadAllLines(path).Select(a => a.Split(';'));
    var csv = (from line in lines               
               select (from col in line
               select col).Skip(1).ToArray() // skip the first column
              ).Skip(2).ToArray(); // skip 2 headlines

如果您需要在进一步处理数据之前对其进行塑形,这是非常有用的(假设前两行由标题组成,而第一列是行标题—您不需要在数组中拥有行标题,因为您只想考虑数据)。

注意:您可以通过使用以下代码轻松获得标题和第一列:

    var coltitle = (from line in lines 
                    select line.Skip(1).ToArray() // skip 1st column
                   ).Skip(1).Take(1).FirstOrDefault().ToArray(); // take the 2nd row
    var rowtitle = (from line in lines select line[0] // take 1st column
                   ).Skip(2).ToArray(); // skip 2 headlines

这个代码示例假设你的*.csv文件的结构如下:

注意:如果你需要跳过空行——有时这很方便,你可以通过插入来实现

    where line.Any(a=>!string.IsNullOrWhiteSpace(a))

在上面的LINQ代码示例中的from和select语句之间。

你可以这样做:

using System.IO;

static void Main(string[] args)
{
    using(var reader = new StreamReader(@"C:\test.csv"))
    {
        List<string> listA = new List<string>();
        List<string> listB = new List<string>();
        while (!reader.EndOfStream)
        {
            var line = reader.ReadLine();
            var values = line.Split(';');

            listA.Add(values[0]);
            listB.Add(values[1]);
        }
    }
}