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?
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
LINQ:
var lines = File.ReadAllLines("test.txt").Select(a => a.Split(';'));
var csv = from line in lines
select (from piece in line
select piece);
^^错误-尼克编辑
原来的应答者似乎试图用一个2维数组填充csv -一个包含数组的数组。第一个数组中的每一项都包含一个表示行号的数组,嵌套数组中的每一项都包含该特定列的数据。
var csv = from line in lines
select (line.Split(',')).ToArray();
其他回答
我有一个图书馆,正是你所需要的。
前段时间,我写了一个简单而快速的库来处理CSV文件。你可以通过以下链接找到它:https://github.com/ukushu/DataExporter/blob/master/Csv.cs
它与CSV的工作方式类似于二维数组。正是你需要的。
例如,如果你需要第三行的所有值,你只需要写:
Csv csv = new Csv();
csv.FileOpen("c:\\file1.csv");
var allValuesOf3rdRow = csv.Rows[2];
或者读取第3行第2单元格:
var value = csv.Rows[2][1];
LINQ:
var lines = File.ReadAllLines("test.txt").Select(a => a.Split(';'));
var csv = from line in lines
select (from piece in line
select piece);
^^错误-尼克编辑
原来的应答者似乎试图用一个2维数组填充csv -一个包含数组的数组。第一个数组中的每一项都包含一个表示行号的数组,嵌套数组中的每一项都包含该特定列的数据。
var csv = from line in lines
select (line.Split(',')).ToArray();
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。
您可以使用c#中的Microsoft.VisualBasic.FileIO.TextFieldParser dll来获得更好的性能
从上面的文章中获取下面的代码示例
static void Main()
{
string csv_file_path=@"C:\Users\Administrator\Desktop\test.csv";
DataTable csvData = GetDataTabletFromCSVFile(csv_file_path);
Console.WriteLine("Rows count:" + csvData.Rows.Count);
Console.ReadLine();
}
private static DataTable GetDataTabletFromCSVFile(string csv_file_path)
{
DataTable csvData = new DataTable();
try
{
using(TextFieldParser csvReader = new TextFieldParser(csv_file_path))
{
csvReader.SetDelimiters(new string[] { "," });
csvReader.HasFieldsEnclosedInQuotes = true;
string[] colFields = csvReader.ReadFields();
foreach (string column in colFields)
{
DataColumn datecolumn = new DataColumn(column);
datecolumn.AllowDBNull = true;
csvData.Columns.Add(datecolumn);
}
while (!csvReader.EndOfData)
{
string[] fieldData = csvReader.ReadFields();
//Making empty value as null
for (int i = 0; i < fieldData.Length; i++)
{
if (fieldData[i] == "")
{
fieldData[i] = null;
}
}
csvData.Rows.Add(fieldData);
}
}
}
catch (Exception ex)
{
}
return csvData;
}
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();