Writing csv file from C# [duplicate]

Question

I have my insertion into text file code as:

foreach (var kvauthor in _tauthorData)
{
   foreach (var coAuthor in kvauthor.Value.CoAuthors)
   {
      twObjClus.WriteLine("AuthorID: {0}, AuthorName: {1}, ClusterID: {2}, PaperID: {3},  
                           CoAuthors: {4}, PaperCategory: {5}, Venue: {6}, Year: {4}",  
                           eAuthor.AuthorID, eAuthor.AuthorName, curCluster.GetClusterID(),  
                           kvauthor.Key, coAuthor, kvauthor.Value.PaperCategory,  
                           kvauthor.Value.VenueID, kvauthor.Value.Year);

   }
}

I want to insert all these data into a csv file whereas I've tried this as:

var csv = new StringBuilder();  

foreach (var kvauthor in _tauthorData)
{
   foreach (var coAuthor in kvauthor.Value.CoAuthors)
   {
      csv.AppendFormat("{0},{1},{2},{3},{4},{5},{6}",AuthorID: {0}, AuthorName: {1}, ClusterID: {2}, PaperID: {3},  
                           CoAuthors: {4}, PaperCategory: {5}, Venue: {6}, Year: {4}",  
                           eAuthor.AuthorID, eAuthor.AuthorName, curCluster.GetClusterID(),  
                           kvauthor.Key, coAuthor, kvauthor.Value.PaperCategory,  
                           kvauthor.Value.VenueID, kvauthor.Value.Year);

   }
}

How can I insert this data row by row into csv file with column headers?

This is not the case, my data to be written is from variables in the code — maliks
– maliks, Commented Jul 25, 2016 at 11:18
Whereas I need to have Column headers at the top and values in csv format — maliks
– maliks, Commented Jul 25, 2016 at 11:18
Try to tell what you can't do. Append line to file? Or maybe you don't know what is csv-file ? Maybe the problem is how to insert column headers? — Sinatr
– Sinatr, Commented Jul 25, 2016 at 11:19
That's easy. You have to create file (or StringBuilder) and add column headers line once outside (before) cycle. Then in the cycle you just add data into corresponding columns (typically using indexes). — Sinatr
– Sinatr, Commented Jul 25, 2016 at 11:22

Josiah Keller · Accepted Answer · 2019-08-02 20:47:24Z

-1

Adding column headers is trivial, just do it once (when opening file or creating instance of e.g. StringBuilder which will be used to add rows later).

var csv = new StringBuilder();  

// add column headers first
csv.AppendLine("AuthorID,AuthorName, ..."); // and so on

// add data
foreach (var kvauthor in _tauthorData)
    foreach (var coAuthor in kvauthor.Value.CoAuthors)
    {
        csv.AppendLine($"{coAuthor.AuthorId},{coAuthor.Name}, ..."); // and so on
        // if you don't have C# 6.0
        // csv.AppendFormat("{0},{1}, ... {N}", coAuthor.AuthorId, coAuthor.Name, ..., Environmental.NewLine");
    }

File.WriteAllText(path, csv.ToString());

Note: you can use AppendLine to add Environmental.NewLine automatically, otherwise (if using AppendFormat) add it to the end of string manually.

edited Aug 2, 2019 at 20:47

Josiah Keller

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answered Jul 25, 2016 at 11:31

Sinatr

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5 Comments

maliks Over a year ago

There is some error i.e. ) expected

maliks Over a year ago

I've used it as

csv.AppendLine($"{eAuthor.AuthorID},{eAuthor.AuthorName},{curCluster.GetClusterID()},{kvauthor.Key},{coAuthor},{kvauthor.Value.PaperCategory},{kvauthor.Value.VenueID},{kvauthor.Value.Year}");

but getting error i.e. ) expected

maliks Over a year ago

Also the $ sign unexpected

Sinatr Over a year ago

If you seek debug help, then post your code and exact error message (as a new question of course). I am not able to help with information given in that comment line. If you don't have interpolated strings (require C# 6.0), then you have to use string.Format() or keep as you do now AppendLine, but simply add Environmental.NewLine at the end (as per note in the answer).

Sinatr Over a year ago

See edit. C# 7.0 is soon...

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