Filtering Columnar Data

[Josh Mellicker]

On Jul 16, 2007, at 2:04 PM, Gregory Lypny wrote:

> I tested the function below, which is much like Josh's, and it  
> filters more than 300 lines in 1 tick; the same code as a message  
> handler rather than a function takes 5 ticks; and the filter  
> command on the same data takes 39 ticks.


Wow, I thought that handler was fast, but never tested/compared it.

I wonder if sorting the lines by columnNum, then exiting on the first  
non-matching line would be faster or slower?



>
> function filterByColumn theData,columnNum, theSearchString
>   -- This function filters tab-delimited data by column
>   if columnNum is an integer
>   then
>     set the itemDelimiter to tab
>     repeat for each line thisLine in theData
>       if item columnNum of thisLine is theSearchString
>       then
>         put thisLine & return after filteredData
>       end if
>     end repeat
>     delete the last character of filteredData
>     return filteredData
>   else
>     return "The column number must be an integer."
>   end if
> end filterByColumn