Data Structure for a table? -

i need create table many rows , more 2 columns. suggest , fast data structure. won't updating , deleting entries table. using lookup functions.
example, have table:

     | column 1 | column 2 | column 3|  | asd      | awd      | asfc    | b  | asgf     | aasf     | asgfc   | 

i have:

 string = "column 1" string b = "b" string c = find(a,b); 

at end value in c should asgf.

you must use associative arrays (so called dictionaries), based on hash-tables. average time-complexity lookup — o(1 + n/k) , o(n) in worst case. must organize table dictionary of columns (with column names key). , column must dictionary of values (with row names key)

more info:

http://en.wikipedia.org/wiki/dictionary_(data_structure) http://en.wikipedia.org/wiki/hash_table

example in c#:

using system; using system.collections; using system.collections.generic;  namespace test {     public class test     {         class table {             class column {                 public dictionary<string, string> cells;                  public column() {                     cells = new dictionary<string, string>();                 }                  public string find(string rowname) {                     string resultvalue;                     if (cells.trygetvalue(rowname, out resultvalue))                          return resultvalue;                     else                         throw new exception("oops, no such cell");                 }             }              dictionary<string, column> columns;             list<string> rownames;              public table() {                 columns = new dictionary<string, column>();                 rownames = new list<string>();             }              public void addcolumn(string columnname, params string[] values) {                 column column = new column();                 columns.add(columnname, column);                  // fill new cells                 int counter = 0;                 foreach (string rowname in rownames) {                     if (counter < values.length)                         column.cells.add(rowname, values[counter]);                     else                         column.cells.add(rowname, "");                     counter++;                 }             }              public void addrow(string rowname, params string[] values) {                 rownames.add(rowname);                  // fill new cells                 int counter = 0;                 foreach (keyvaluepair<string, column> columnpair in columns) {                     column column = columnpair.value;                     if (counter < values.length)                         column.cells.add(rowname, values[counter]);                     else                         column.cells.add(rowname, "");                     counter++;                 }             }              public string find(string columnname, string rowname) {                 column resultcolumn;                 if (columns.trygetvalue(columnname, out resultcolumn))                     return resultcolumn.find(rowname);                 else                     throw new exception("oops, no such cell");             }         }          public static void main()         {             table table = new table();             table.addrow("a");             table.addrow("b");             table.addcolumn("column 1", "asd", "asgf");             table.addcolumn("column 2", "awd", "aasf");             table.addcolumn("column 3", "asfc", "asgfc");             console.writeline(table.find("column 1", "b") );         }     } }