Filtering Columnar Data

Josh Mellicker josh at dvcreators.net
Tue Jul 17 22:15:07 CDT 2007


Nice.

Once again, I suggest not hardwiring theColNum because it could  
change... but you could always make a separate handler that figured  
out the column number from a header row, lookup table or other  
criteria, then call this handler.


On Jul 17, 2007, at 1:26 PM, Gregory Lypny wrote:

> Hello Josh,
>
> Here's the final version of the function.  Thanks to everyone for  
> their suggestions.  I know there are other features and better  
> error-checking that can be added.  Maybe later.  It can extract  
> roughly 75 records from 700 in 1 tick on an Intel-based iMac.
>
> Regards,
>
> 	Gregory
>
> function filteredByColumn theData,theColNum,theSearchString,isWithout
>   -- This function filters tab-delimited data by column
>   -- By default the filter extracts lines containing the search  
> string.  Make isWithout = "without" to extract lines without it.
>   -- Possible mods: options to make "begins with" or "contains"  
> searches
>   if theColNum is an integer
>   then
>     set the itemDelimiter to tab
>     if isWithout is empty
>     then
>       sort lines of theData by (item theColNum of each is not  
> theSearchString)  -- Brings lines with theSearchString to the top
>       repeat for each line thisLine in theData
>         if item theColNum of thisLine is theSearchString
>         then
>           put thisLine & return after filteredData
>         else
>           exit repeat
>         end if
>       end repeat
>     else
>       sort lines of theData by (item theColNum of each is  
> theSearchString)  -- Brings lines without theSearchString to the top
>       repeat for each line thisLine in theData
>         if item theColNum of thisLine is not theSearchString
>         then
>           put thisLine & return after filteredData
>         else
>           exit repeat
>         end if
>       end repeat
>     end if
>     delete the last character of filteredData
>     return filteredData
>   else
>     return "The column number must be an integer."
>   end if
> end filteredByColumn
>
>
>
>
>
>
> On Mon, Jul 16, 2007, at 7:49 PM, Josh Mellicker responded:
>
>> 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?
>>
>
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