c# - How to select first n number of columns from a DataTable -

i have datatable containing dynamic number of rows , dynamic number of columns,

col1        col2        col3        col4............coln ________________________________________________________________________ row1col1    row1col2    row1col3    row1col4........row1coln .           .               .       .               . .           .               .       .               . .           .               .       .               . .           .               .       .               . .           .               .       .               . .           .               .       .               . rowncol1    rowncol2    rowncol3    rowncol4.......rowncoln 

how select data first n number of columns datatable?

to columns:

   var tbl = new system.data.datatable(); var cols = tbl.columns.cast<system.data.datacolumn>().take(20); 

// if wish first 20 columns...

if want data, have loop through columns data.

var data = cols.selectmany(x => tbl.rows.cast().take(100).select(y => y[x]));

of course, dump data ienumerable, if want use strong typed object or list of 1 dimensional array, believe it's simple, example:

var data2 = cols.select(x => tbl.rows.cast().take(100).select(y => y[x]).toarray());

if wish keep current table , reserve number of columns/rows, can remove rest columns/rows:

        var tbl = new system.data.datatable();         int totalcolumnstoreserve = 20;         (int = tbl.columns.count - 1; >= totalcolumnstoreserve; i--)         {             tbl.columns.removeat(i);         }          int totalrowstoreserve = 100;         (int = tbl.rows.count - 1; >= totalrowstoreserve; i--)         {             tbl.rows.removeat(i);         }