jozne
asked on
how to make faster code - my code has too many FOR sentences(?)
ok here is my code. I need better option for doing this thing, since
this way is TOO SLOW for my purposes and I can't figure out any other / faster way
to do it. so if someone could help me with this it would be GREAT! :)
and, for qui = 1 to 1000 is there, because this code that I have there, is going
to run OVER 1000 times before finish, so I added it to see the delay in 1000 times. If someone could squeez the time that code runs to even ½, it would be big help. I guess that those FOR
sentences makes the code run longer and if there would be a way to do this without running so many FOR 's the speed would drop.. dunno :o
so here's the code (coordinates are in memory string, example -> x,y-x,y-x,y where the "-" is separator)
sub do_things()
timestart = Time
memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
For qui = 1 To 1000
char_start = 1
pituus_memory = Len(memory)
For q = 1 To pituus_memory
If Mid(memory, q, 1) = "," Then coord_num = coord_num + 1
Next
For coordinates = 1 To coord_num
char_count = 0
For pepe = char_start To pituus_memory
If Mid(memory, pepe, 1) <> "-" Then char_count = char_count + 1
If Mid(memory, pepe, 1) = "-" Then Exit For
Next
If "5,123" = Mid(memory, char_start, char_count) Then Exit For
char_start = char_start + char_count + 1
Next
Next
timeend = Time
MsgBox timestart & " -- " & timeend
end sub
if you have questions, ask and I'll give more details. so this is a part of my bigger code where I have about ~6000 memory strings to check, so don't mind the for qui = 1 to 1000
this way is TOO SLOW for my purposes and I can't figure out any other / faster way
to do it. so if someone could help me with this it would be GREAT! :)
and, for qui = 1 to 1000 is there, because this code that I have there, is going
to run OVER 1000 times before finish, so I added it to see the delay in 1000 times. If someone could squeez the time that code runs to even ½, it would be big help. I guess that those FOR
sentences makes the code run longer and if there would be a way to do this without running so many FOR 's the speed would drop.. dunno :o
so here's the code (coordinates are in memory string, example -> x,y-x,y-x,y where the "-" is separator)
sub do_things()
timestart = Time
memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
For qui = 1 To 1000
char_start = 1
pituus_memory = Len(memory)
For q = 1 To pituus_memory
If Mid(memory, q, 1) = "," Then coord_num = coord_num + 1
Next
For coordinates = 1 To coord_num
char_count = 0
For pepe = char_start To pituus_memory
If Mid(memory, pepe, 1) <> "-" Then char_count = char_count + 1
If Mid(memory, pepe, 1) = "-" Then Exit For
Next
If "5,123" = Mid(memory, char_start, char_count) Then Exit For
char_start = char_start + char_count + 1
Next
Next
timeend = Time
MsgBox timestart & " -- " & timeend
end sub
if you have questions, ask and I'll give more details. so this is a part of my bigger code where I have about ~6000 memory strings to check, so don't mind the for qui = 1 to 1000
sorry i forgot this after the Next
timeend = Time
MsgBox timestart & " -- " & timeend
end sub
timeend = Time
MsgBox timestart & " -- " & timeend
end sub
You can save lots of time by using the Split function instead of this loop:
For q = 1 To pituus_memory
If Mid(memory, q, 1) = "," Then coord_num = coord_num + 1
Next
'=========================
Sub do_things()
Dim TimeStart As Date, TimeEnd As Date
Dim Memory As String
Dim qui As Long
Dim char_start As Long
Dim pituus_memory As Long
Dim q As Long
Dim coord_num As Long
Dim coordinates As Long
Dim char_count As Long
Dim pepe As Long
Dim splitarray() As String
TimeStart = Time
Memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
For qui = 1 To 1000
'' pituus_memory = Len(Memory)
'' For q = 1 To pituus_memory
'' If Mid(Memory, q, 1) = "," Then coord_num = coord_num + 1
'' Next
splitarray = Split(Memory, ",")
coord_num = UBound(splitarray)
char_start = 1
For coordinates = 1 To coord_num
char_count = 0
For pepe = char_start To Len(Memory)
If Mid(Memory, pepe, 1) <> "-" Then char_count = char_count + 1
If Mid(Memory, pepe, 1) = "-" Then Exit For
Next
If "5,123" = Mid(Memory, char_start, char_count) Then Exit For
char_start = char_start + char_count + 1
Next
Next
TimeEnd = Time
Debug.Print qui
MsgBox Format(TimeEnd - TimeStart, "hh:nn:ss")
End Sub
For q = 1 To pituus_memory
If Mid(memory, q, 1) = "," Then coord_num = coord_num + 1
Next
'=========================
Sub do_things()
Dim TimeStart As Date, TimeEnd As Date
Dim Memory As String
Dim qui As Long
Dim char_start As Long
Dim pituus_memory As Long
Dim q As Long
Dim coord_num As Long
Dim coordinates As Long
Dim char_count As Long
Dim pepe As Long
Dim splitarray() As String
TimeStart = Time
Memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
For qui = 1 To 1000
'' pituus_memory = Len(Memory)
'' For q = 1 To pituus_memory
'' If Mid(Memory, q, 1) = "," Then coord_num = coord_num + 1
'' Next
splitarray = Split(Memory, ",")
coord_num = UBound(splitarray)
char_start = 1
For coordinates = 1 To coord_num
char_count = 0
For pepe = char_start To Len(Memory)
If Mid(Memory, pepe, 1) <> "-" Then char_count = char_count + 1
If Mid(Memory, pepe, 1) = "-" Then Exit For
Next
If "5,123" = Mid(Memory, char_start, char_count) Then Exit For
char_start = char_start + char_count + 1
Next
Next
TimeEnd = Time
Debug.Print qui
MsgBox Format(TimeEnd - TimeStart, "hh:nn:ss")
End Sub
Always tell your Next statements what is next i.e for i=1 to 10 next i. This gives a slight improvment in execution time.
ASKER CERTIFIED SOLUTION
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Erick's code 0.598 s
My Code 0.012 s
These are for 10000 iterations of the main loop, so both represent significant optimization over the original, however, mine is many times faster than Erick's. Your performance may vary depending on the real life data you have, but my approach will be significantly faster than a looping comparison.
Using "Next i" instead of "Next" if it has any effect at all, which I'm not convinced, is not enough of an optimization to even mention. I've done a fair amount of testing, and have yet to see any difference.
My Code 0.012 s
These are for 10000 iterations of the main loop, so both represent significant optimization over the original, however, mine is many times faster than Erick's. Your performance may vary depending on the real life data you have, but my approach will be significantly faster than a looping comparison.
Using "Next i" instead of "Next" if it has any effect at all, which I'm not convinced, is not enough of an optimization to even mention. I've done a fair amount of testing, and have yet to see any difference.
Are we trying to determine if the coordinate "5,123" exists in the string, or are we trying to determine where in the string "5,123" belongs?
in my code is both if you retrieve the value of :
dim start as integer
dim fin as integer
start=char_start
fin=pituus_memory-end_of_s
these 2 lines myst be added in the if where the found=true
dim start as integer
dim fin as integer
start=char_start
fin=pituus_memory-end_of_s
these 2 lines myst be added in the if where the found=true
ASKER
it is to check if the "5,123" string is in the main Memory string.
Ok...
Sub do_things3()
Dim TimeStart As Single, TimeEnd As Single
Dim Memory As String
Dim sTmpMem As String
Dim sSearch As String
Dim qui As Long
Dim pos As Long
TimeStart = Timer
'the main string
Memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
'what we are looking for
sSearch = "5,123"
sSearch = "-" & sSearch & "-"
For qui = 1 To 10000
sTmpMem = "-" & Memory & "-"
pos = InStr(1, sTmpMem, sSearch)
'If the string exists, pos will point to the character position
'If the string does not exist, then pos will be 0
Next
TimeEnd = Timer
MsgBox Format(TimeEnd - TimeStart, "0.000")
End Sub
Sub do_things3()
Dim TimeStart As Single, TimeEnd As Single
Dim Memory As String
Dim sTmpMem As String
Dim sSearch As String
Dim qui As Long
Dim pos As Long
TimeStart = Timer
'the main string
Memory = "5,2-5,3-5,4-5,5-5,6-5,7-5
'what we are looking for
sSearch = "5,123"
sSearch = "-" & sSearch & "-"
For qui = 1 To 10000
sTmpMem = "-" & Memory & "-"
pos = InStr(1, sTmpMem, sSearch)
'If the string exists, pos will point to the character position
'If the string does not exist, then pos will be 0
Next
TimeEnd = Timer
MsgBox Format(TimeEnd - TimeStart, "0.000")
End Sub
Erick, that's the same as my code, except it doesn't check if the coordinates exist in the first or last position of the string.
Yes it does...
sTmpMem = "-" & Memory & "-"
sTmpMem = "-" & Memory & "-"
Ah, so it does. :)
You are correct Paul, it is the same idea. I looked at the question again because of your idea to search for "-5,123-" I did not know exactly what the code was supposed to do.
jzone - PaulHews gets credit for the algorithm.
One possible bug:
'this evaluates true
ElseIf StrComp(Right$(Memory, 6), "-5,123") Then 'test end
lngPos = Len(Memory) - 4
End If
jzone - PaulHews gets credit for the algorithm.
One possible bug:
'this evaluates true
ElseIf StrComp(Right$(Memory, 6), "-5,123") Then 'test end
lngPos = Len(Memory) - 4
End If
ASKER
what about
check = InStr(1, Memory, "5,123") and if check > 0 then found?
since, I need it only to check if it is in there, nothing else...
check = InStr(1, Memory, "5,123") and if check > 0 then found?
since, I need it only to check if it is in there, nothing else...
That would also match "25,1234"
ASKER
ok thanks :)
btw. is there any faster way than For...Next to do this
path(1) = "1"
path(2) = "2"
path(3) = "3"
path(4) = "4"
for i = 1 to 5 'should push all path(i) to 1 up
if path(0) = "" then path(0) = path(1): helper = i
if path(0) <> "" then path(helper) = path(i): helper = i
next i
'resulting path(0) = 1, path(1) = 2, path(2) = 3, path(3) = 4
And thanks to you paul, I'll be closing the question soon :)
btw. is there any faster way than For...Next to do this
path(1) = "1"
path(2) = "2"
path(3) = "3"
path(4) = "4"
for i = 1 to 5 'should push all path(i) to 1 up
if path(0) = "" then path(0) = path(1): helper = i
if path(0) <> "" then path(helper) = path(i): helper = i
next i
'resulting path(0) = 1, path(1) = 2, path(2) = 3, path(3) = 4
And thanks to you paul, I'll be closing the question soon :)
Good point Erick, should be:
ElseIf StrComp(Right$(Memory, 6), "-5,123") = 0 Then 'test end
lngPos = Len(Memory) - 4
End If
Although since we just need to test for existence, the version you provided would be fastest.
>btw. is there any faster way than For...Next to do this
No, you will have to touch each member of the array, and the fastest way would be a for ... next loop. If your array is small that won't be a problem.
Something like this?
For i = Lbound(path) to Ubound(path)
path(i) = Cint(path(i)) + 1
Next i
ElseIf StrComp(Right$(Memory, 6), "-5,123") = 0 Then 'test end
lngPos = Len(Memory) - 4
End If
Although since we just need to test for existence, the version you provided would be fastest.
>btw. is there any faster way than For...Next to do this
No, you will have to touch each member of the array, and the fastest way would be a for ... next loop. If your array is small that won't be a problem.
Something like this?
For i = Lbound(path) to Ubound(path)
path(i) = Cint(path(i)) + 1
Next i
jozne, thanks for the points. :)
I hope you got what you needed here.
Erick37 I think some points should have gone your way on this answer, which was a collaboration:
https://www.experts-exchange.com/questions/21350278/For-Erick37.html
I hope you got what you needed here.
Erick37 I think some points should have gone your way on this answer, which was a collaboration:
https://www.experts-exchange.com/questions/21350278/For-Erick37.html
you are trying to find in a string memory the characters "5,123" in between 2 "-" and if you find it then you increase qui if not you continue till the end of the string and if still not found then increase qui
the code i see for that should be this way a bit faster:
dim i as integer
dim found as boolean
dim end_of_search as integer 'this is used to store the position of the last char read from the string befor it reads "-"
For qui =1 to 1000
char_start=1
pituus_memory=Len(memory)
end_of_search=0
found=False
Do Until (i=pituus_memory) OR (found=True)
if(Mid(memory,i,1)="-" then
end_of_search=i
if Mid(memory,char_start,pitu
found=True
endif
char_start=end_of_search+1
endif
i=i+1
loop
Next
try this and let me know how it goes
thanks