C# DataTable select columns where column name like

Question

I would like to select all columns in a DataTable that begin with the characters 'hz'. At the moment I am doing this:

var uploadTable = dataTable.DefaultView.ToTable(false, "locID", "hz1582", "hz1581", "hz1580", "hz1579", "hz1578", "hz1577", "hz1576", "hz1575", "hz1574", "hz1573", "hz1572", "hz1571");

However, the 'hz' columns are variable each time I run my code, so I need some way of selecting all columns in the table that begin with hz. Note also that the column 'locID' is always present and needs to be returned. So, I need something like this:

var uploadTable = dataTable.DefaultView.ToTable(false, "locID", "hz%");

Any ideas? Thanks.

What means you need to select the columns? You need to select the rows which column-names start with hz? Or you need to select only the DataColumns without data? — Tim Schmelter
– Tim Schmelter, Commented Mar 8, 2017 at 10:04
I need to select the rows as well. i.e. subset the datatable based on the coluumn names. — Cameron
– Cameron, Commented Mar 8, 2017 at 10:07

Tim Schmelter · Accepted Answer · 2017-03-08 10:10:31Z

9

I would use LINQ for this task:

DataTable uploadtable = dataTable.Copy();
var removeColumns = dataTable.Columns.Cast<DataColumn>()
   .Where(c => !c.ColumnName.StartsWith("hz", StringComparison.InvariantCultureIgnoreCase));

foreach (DataColumn colToRemove in removeColumns)
    uploadtable.Columns.Remove(colToRemove.ColumnName);

answered Mar 8, 2017 at 10:10

Tim Schmelter

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1 Comment

Cameron Over a year ago

Thanks, this looks like just what I need!

Azar Shaikh · Accepted Answer · 2017-03-08 10:17:23Z

1

 string[] columnNames = dt.Columns.Cast<DataColumn>()
                                         .Select(x => x.ColumnName).Where(n => n.Contains("hz")).ToArray();

    var uploadTable = dataTable.DefaultView.ToTable(false, columnNames);

answered Mar 8, 2017 at 10:17

Azar Shaikh

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4 Comments

J.SMTBCJ15 Over a year ago

you linq will not work for Machzor column name?

Azar Shaikh Over a year ago

@J.SMTBCJ15 why?

J.SMTBCJ15 Over a year ago

because @azar he said start with not contains and if column name is Machzor will be considered as column which is not actually

Azar Shaikh Over a year ago

@J.SMTBCJ15 Yes Thanks

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