Deleting Data Woefully Slow

[Kay C Lan]

Mark and Brian,

Thanks for your comments.

Mark you are absolutely right about tests 9, 10 and 11 - it's the problem of
taking my real life situation and simplifying for the List. I've revised the
script and this time TESTED the output to confirm the last  3 create
identical data.

No change, it's still quicker to take a HUGE set of data and recreate a
slightly smaller version of it, than it is to just delete a small amount
from it - although it only applies if you can use 'repeat for each' to
create your new data.

Brian, whilst put line 1 to -2 might be OK if all you want to do is delete
the last line, and I accept I used it in my 'simple' examples, the last
three Tests are more real life, where the line to delete is imbedded
'somewhere' in the data. Interestingly though you again prove the point that
'putting data' in Rev is much faster than 'delete' data.

REVISED test results I got on a MBP 2.16GHz, 2 GB RAM, OS X.6.2, Rev Studio
4.0.0 Build 950

**repeat for each**
put after = 2 ms
delete line -1 = 327 ms
put before = 10 ms
delete line 1 = 9 ms
**repeat with x = **
put after = 158 ms
delete line -1 = 322 ms
put before = 196 ms
delete line 1 = 10 ms
Create 90% - repeat for each = 2 ms
Create 90% - repeat with x = 288 ms
Delete 10% = 199 ms

50000 repeats
**repeat for each**
put after = 19 ms
delete line -1 = 35491 ms
put before = 951 ms
delete line 1 = 934 ms
**repeat with x = **
put after = 18528 ms
delete line -1 = 35208 ms
put before = 18872 ms
delete line 1 = 929 ms
Create 90% - repeat for each = 26 ms
Create 90% - repeat with x = 33341 ms
Delete 10% = 19790 ms

The REVISION 3 script I used:

on mouseUp
   repeat 50000 times
      put random (9) & cr after tData
   end repeat
   --test 1
   put the millisec into tStart
   repeat for each line tLine in tData
      put tLine & cr after tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal1
   --test 2
   put the millisec into tStart
   repeat for each line tLine in tData
      delete line -1 of tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal2
   --test 3
   put the millisec into tStart
   repeat for each line tLine in tData
      put tLine & cr before tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal3
   --test 4
   put the millisec into tStart
   repeat for each line tLine in tData
      delete line 1 of tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal4
   --test 5
   put the millisec into tStart
   repeat with tCounter = 1 to the number of lines of tData
      put line tCounter of tData & cr after tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal5
   --test 6 ***REVISED***
   put the millisec into tStart
   repeat with tCounter = 1 to the number of lines of tData
      delete line -1 of tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal6
   --test 7
   put the millisec into tStart
   repeat with tCounter = 1 to the number of lines of tData
      put line tCounter of tData & cr before tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal7
   --test 8
   put the millisec into tStart
   repeat with tCounter = 1 to the number of lines of tData
      delete line 1 of tData1
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal8
   --test 9  ***REVISED***
   put the millisec into tStart
   repeat for each line tLine in tData
      if NOT(tLIne contains 1) then
         put tLine & cr after tData1
      end if
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal9
   --test 10 ***REVISED***
   put the millisec into tStart
   repeat with tCounter = 1 to the number of lines of tData
      if NOT(line tCounter of tData contains 1) then
         put line tCounter of tData & cr after tData2
      end if
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal10
   --test 11 ***REVISED***
   put tData into tData3
   put the millisec into tStart
   repeat with tCounter = the number of lines of tData down to 1
      if (line tCounter of tData contains 1) then
         delete line tCounter of tData3
      end if
   end repeat
   put the millisec into tEnd
   put tEnd - tStart into tTotal11

   put "**repeat for each**" & cr into msg
   put "put after = " & tTotal1 & " ms" & cr after msg
   put "delete line -1 = " & tTotal2 & " ms" & cr after msg
   put "put before = " & tTotal3 & " ms" & cr after msg
   put "delete line 1 = " & tTotal4 & " ms" & cr after msg
   put "**repeat with x = **" & cr after msg
   put "put after = " & tTotal5 & " ms" & cr after msg
   put "delete line -1 = " & tTotal6 & " ms" & cr after msg
   put "put before = " & tTotal7 & " ms" & cr after msg
   put "delete line 1 = " & tTotal8 & " ms" & cr after msg
   put "Create 90% - repeat for each = " & tTotal9 & " ms" & cr after msg
   put "Create 90% - repeat with x = " & tTotal10 & " ms" & cr after msg
   put "Delete 10% = " & tTotal11 & " ms" & cr after msg
end mouseUp