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TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 4:48 am
by Mistrel
Pretty simple. This trims characters only from a specific side of the string.
Code: Select all
Procedure.s TrimLeft(String.s, Character.c)
Protected *Trim.Trim_Char
Protected Offset
Protected i
If Not String.s Or Not Character.c
ProcedureReturn String.s
EndIf
*Trim=@String.s
For i=1 To Len(String.s)
If *Trim\Char[i-1]=Character.c
Offset+1
Else
Break
EndIf
Next i
If Not Offset
ProcedureReturn String.s
EndIf
ProcedureReturn Mid(String.s,Offset+1,Len(String.s)-Offset)
EndProcedure
Procedure.s TrimRight(String.s, Character.c)
Protected *Trim.Trim_Char
Protected Offset
Protected i
If Not String.s Or Not Character.c
ProcedureReturn String.s
EndIf
*Trim=@String.s
For i=Len(String.s) To 1 Step -1
If *Trim\Char[i-1]=Character.c
Offset+1
Else
Break
EndIf
Next i
If Not Offset
ProcedureReturn String.s
EndIf
ProcedureReturn Mid(String.s,1,Len(String.s)-Offset)
EndProcedure
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 5:48 am
by STARGÅTE
What is different to LTrim() and RTrim() from PB ?
Code: Select all
Debug LTrim("...This is Art...", ".")
Debug RTrim("...Hello Word...", ".")
and your code ist bugy :
Code: Select all
Debug TrimLeft("...This is Art....", '.')
Debug TrimRight("...Hello Word....", '.')
is Art....
...Hello W
You forgot a break, so he counts the sign at the other end!
Code: Select all
If *Trim\Char[i-1]=Character.c
Offset+1
Else
Break ; << !
EndIf
And so on:
Mid(String.s,1,Len(String.s)-Offset) ===>> Left(String, Len(String.s)-Offset)
Mid(String.s,Offset+1,Len(String.s)-Offset) ===>> Right(String, Len(String.s)-Offset)
And
is not good, because you count new each loop the length of String
Better:
Code: Select all
Protected Length = Len(String)
For i=1 To Length
Edit: :roll: oky ^^
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 5:53 am
by Mistrel
You know what.. I never knew we had those functions.
Thanks for pointing out a bug, too.
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 6:00 am
by Nituvious
Mistrel, I think you single handedly are keeping Tricks 'n' Tips alive! Thank you so much for the neat code snippets!
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 6:56 am
by Mistrel
I have some pretty amazing stuff I can't wait to put up. But a lot of it isn't quite there yet. So there are still some exciting things to come.
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 5:26 pm
by WilliamL
Code: Select all
SELECT ALL
For i=1 To Len(String.s)
is not good, because you count new each loop the length of String (length of String has to be calculated each loop of For/Next)
Better:
Code: Select all
SELECT ALL
Protected Length = Len(String)
For i=1 To Length
Is that true? That could be quite a speed difference!
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 5:40 pm
by eesau
If I understood correctly, it's not true, both ways are basically the same.
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 5:47 pm
by STARGÅTE
<<
"Is that true?"
Yes:
@eesau: No !
Example:
Code: Select all
Procedure.i MyLen(String.s)
Debug "Len("+String+")"
ProcedureReturn Len(String)
EndProcedure
String.s = "Example"
For i=1 To MyLen(String)
String = Left(String, Len(String)-1)
Next
Len(Example)
Len(Exampl)
Len(Examp)
Len(Exam)
Len(Exa)
the expression behind
To run with each loop, always
Code: Select all
#Size = 100000
Space$ = Space(100)
Time = ElapsedMilliseconds()
For n = 1 To #Size
For i = 1 To Len(Space$)
Next
Next
Time1 = ElapsedMilliseconds()-Time
Time = ElapsedMilliseconds()
For n = 1 To #Size
Len = Len(Space$)
For i = 1 To Len
Next
Next
Time2 = ElapsedMilliseconds()-Time
MessageRequester("", "Time1: "+Str(Time1)+Chr(10)+"Time2: "+Str(Time2))
Time1: 688
Time2: 16
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 6:00 pm
by eesau
A-ha, that's interesting!
Re: TrimLeft and TrimRight
Posted: Tue Oct 19, 2010 6:11 pm
by WilliamL
I've run into this very problem slowing down programs and used this work-around.
Interesting, indeed!