the best way to convert delimited to fixed width

Question

What is the BEST way to convert this :

FirstName,LastName,Title,BirthDate,HireDate,City,Region
Nancy,Davolio,Sales Representative,1948-12-08,1992-05-01,Seattle,WA
Andrew,Fuller,Vice President Sales,1952-02-19,1992-08-14,Tacoma,WA
Janet,Leverling,Sales Representative,1963-08-30,1992-04-01,Kirkland,WA
Margaret,Peacock,Sales Representative,1937-09-19,1993-05-03,Redmond,WA
Steven,Buchanan,Sales Manager,1955-03-04,1993-10-17,London,NULL
Michael,Suyama,Sales Representative,1963-07-02,1993-10-17,London,NULL
Robert,King,Sales Representative,1960-05-29,1994-01-02,London,NULL
Laura,Callahan,Inside Sales Coordinator,1958-01-09,1994-03-05,Seattle,WA
Anne,Dodsworth,Sales Representative,1966-01-27,1994-11-15,London,NULL

to this :

FirstName  LastName             Title                          BirthDate   HireDate   City            Region
---------- -------------------- ------------------------------ ----------- ---------- --------------- ---------------
Nancy      Davolio              Sales Representative           1948-12-08  1992-05-01  Seattle         WA
Andrew     Fuller               Vice President, Sales          1952-02-19  1992-08-14  Tacoma          WA
Janet      Leverling            Sales Representative           1963-08-30  1992-04-01  Kirkland        WA
Margaret   Peacock              Sales Representative           1937-09-19  1993-05-03  Redmond         WA
Steven     Buchanan             Sales Manager                  1955-03-04  1993-10-17  London          NULL
Michael    Suyama               Sales Representative           1963-07-02  1993-10-17  London          NULL
Robert     King                 Sales Representative           1960-05-29  1994-01-02  London          NULL
Laura      Callahan             Inside Sales Coordinator       1958-01-09  1994-03-05  Seattle         WA
Anne       Dodsworth            Sales Representative           1966-01-27  1994-11-15  London          NULL

Answer 1

May I suggest you take a look at String.Split(Char[]). The rest should be trivial.

Answer 2

I'd create a custom class to hold the information, then do a loop for each line in the CSV file, split on the comma and fill your custom object up. Then throw all of them into a list or IEnumrable and throw it into a repeater / datagrid.

public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Title { get; set; }
        public DateTime BirthDate { get; set; }
        public DateTime HireDate { get; set; }
        public string City { get; set; }
        public string Region { get; set; }
    }

    public void Parse(string csv)
    {
        string[] lines = csv.Split( Environment.NewLine.ToCharArray() );
                    List<Person> persons = new List<Person>();

        foreach (string line in lines)
        {
            string[] values = line.Split( ',' );

            Person p = new Person();

            p.FirstName = values[ 0 ];
            p.LastName = values[ 1 ];

                            persons.Add( p );
            //.... etc etc
        }
    }

Answer 3

This meets your requirements as stated, and uses LINQ (since your question was tagged LINQ), but is not necessarily best:

class Program
{
    static void Main(string[] args)
    {
        List<string> inputs = new List<string>
        {
            "FirstName,LastName,Title,BirthDate,HireDate,City,Region",
            "Nancy,Davolio,Sales Representative,1948-12-08,1992-05-01,Seattle,WA",
            "Andrew,Fuller,Vice President Sales,1952-02-19,1992-08-14,Tacoma,WA",
            "Janet,Leverling,Sales Representative,1963-08-30,1992-04-01,Kirkland,WA",
            "Margaret,Peacock,Sales Representative,1937-09-19,1993-05-03,Redmond,WA",
            "Steven,Buchanan,Sales Manager,1955-03-04,1993-10-17,London,NULL",
            "Michael,Suyama,Sales Representative,1963-07-02,1993-10-17,London,NULL",
            "Robert,King,Sales Representative,1960-05-29,1994-01-02,London,NULL",
            "Laura,Callahan,Inside Sales Coordinator,1958-01-09,1994-03-05,Seattle,WA",
            "Anne,Dodsworth,Sales Representative,1966-01-27,1994-11-15,London,NULL"
        };

        // TODO: These widths would presumably be configurable
        List<int> widths = new List<int> { 12, 22, 32, 13, 12, 17, 8 };

        List<string> outputs = inputs.Select(s => ToFixedWidths(s, ',', widths)).ToList();

        outputs.ForEach(s => System.Diagnostics.Debug.WriteLine(s));

        Console.ReadLine();
    }

    private static string ToFixedWidths(string s, char separator, List<int> widths)
    {
        List<string> split = s.Split(separator).ToList();

        // TODO: Error handling - what if there are more/less separators in
        // string s than we have width values?

        return string.Join(String.Empty, split.Select((ss, i) => ss.PadRight(widths[i], ' ')).ToArray());
    }
}

In a production scenario though I'd expect to see this data read into an appropriate Person class, as Matt recommended in his answer.

Answer 4

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace StringParsingWithLinq
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var inputs = new List<string>
                             {
                                 "FirstName,LastName,Title,BirthDate,HireDate,City,Region",
                                 "Nancy,Davolio,Sales Representative,1948-12-08,1992-05-01,Seattle,WA",
                                 "Andrew,Fuller,\"Vice President, Sales\",1952-02-19,1992-08-14,Tacoma,WA",
                                 "Janet,Leverling,Sales Representative,1963-08-30,1992-04-01,Kirkland,WA",
                                 "Margaret,Peacock,Sales Representative,1937-09-19,1993-05-03,Redmond,WA",
                                 "Steven,Buchanan,Sales Manager,1955-03-04,1993-10-17,London,NULL",
                                 "Michael,Suyama,Sales Representative,1963-07-02,1993-10-17,London,NULL",
                                 "Robert,King,Sales Representative,1960-05-29,1994-01-02,London,NULL",
                                 "Laura,Callahan,Inside Sales Coordinator,1958-01-09,1994-03-05,Seattle,WA",
                                 "Anne,Dodsworth,Sales Representative,1966-01-27,1994-11-15,London,NULL"
                             };

            Console.Write(FixedWidthHelper.ReadLines(inputs)
                              .ToFixedLengthString());
            Console.ReadLine();
        }

        #region Nested type: FixedWidthHelper

        public class FixedWidthHelper
        {
            private readonly Regex _csvRegex = new Regex(",(?=(?:[^\"]*\"[^\"]*\")*(?![^\"]*\"))");
            private readonly List<string[]> _data = new List<string[]>();
            private List<int> _fieldLen;

            public static FixedWidthHelper ReadLines(List<string> lines)
            {
                var fw = new FixedWidthHelper();
                lines.ForEach(fw.AddDelimitedLine);
                return fw;
            }

            private void AddDelimitedLine(string line)
            {
                string[] fields = _csvRegex.Split(line);

                if (_fieldLen == null)
                    _fieldLen = new List<int>(fields.Select(f => f.Length));

                for (int i = 0; i < fields.Length; i++)
                {
                    if (fields[i].Length > _fieldLen[i])
                        _fieldLen[i] = fields[i].Length;
                }

                _data.Add(fields);
            }

            public string ToFixedLengthString()
            {
                var sb = new StringBuilder();
                foreach (var list in _data)
                {
                    for (int i = 0; i < list.Length; i++)
                    {
                        sb.Append(list[i].PadRight(_fieldLen[i] + 1, ' '));
                    }
                    sb.AppendLine();
                }

                return sb.ToString();
            }
        }

        #endregion
    }
}

Answer 5

You have two problems here. Consider them separately and you will find a good solution more easily.

1. Parse your CSV-format input data in to a useful format.

2. Present your data in a certain way

Don't write your own CSV parser. The rules are a little tricky, but the format is well-known. Getting it wrong would be bad in the long run. There are existing CSV libraries in the .NET framework you could call on, but I don't know much about them. However, this problem is perfect for the new dynamic feature in C#. Here's one that looks promising: http://tonikielo.blogspot.com/2010/01/c-40-dynamic-linq-to-csvhe.html

I'm assuming that printing the data is a trivial problem and you don't need our help. If not, you'll need to give us some more information, like how you want to decide the widths of the columns.