Stripping Non Printing Characters

[ShaneMuir]

Hi everybody

I am sure this is quite an easy one for all of you but here goes anyway:

I wish to strip all the non printing characters from an input string. I am aware of the routine Oconv(expression, MCP) but I do not wish to replace the offending character with a period, rather a character of my choice.

I know it can be done as it I have seen it done before, but I cannot remember exactly how.

Thank you in Advance
Shane

[crouse]

ereplace(Oconv(StringWithNonPrintingCharacters, "MCP"),".",MyNewCharacterOfChoice,0,1) will work.

If you might have periods in your string to begin with, do an inner ereplace to change them to a unique character first, then another outer ereplace to change them back to period after converting the non-printing characters.

For execution speed and reusability, do this all in one line and create a transform for it.

For maintainablity and reusability, do it in several lines in a routine.

-Craig

[ray.wurlod]

Welcome aboard! Long way from Brisbane!

About the only way to strip all non-printing characters is to create a Routine that processes each character.

Oconv with "MCA", "MC/A", "MCN", "MC/N" and "MCP" are probably too specific for your needs.

Code: Select all

FUNCTION RemoveNonPrintingCharacters(TheString)
Ans = ""
CharCount = Len(TheString)
For cpos = 1 To CharCount
   TheChar = Seq(TheString[cpos,1])
   If TheChar >= 32 And TheChar <= 127
   Then
      Ans := TheChar
   End
Next cpos
RETURN(Ans)

If you're working with a non-ASCII character set, such as a European character set that includes accented characters, your definition of "printable" may need to change.

If NLS is enabled, prefer UniSeq to Seq.

[ShaneMuir]

Thanks for that guys. Most appreciated.

Shane

PS: Yes Ray I am a long way from Brisbane :D

[hassers]

Very similar to Rays Code, do initial check for null string being received and stip trailing spaces:

Input variable SourceString


Ans = ''
lenvar= len(trimb(SourceString))
if lenvar < 1 then Ans = ' '

For i = 1 to lenvar step 1

char1 = SourceString[i,1]
nchar = seq(char1)

if nchar <32 or nchar>127 then
Ans := ' '
End Else
Ans := char1
End

Next i

[ray.wurlod]

Trailing spaces may be valid data.

NULL would be OK in my routine, because Len(@NULL) is zero (go on, try it). However, my routine would return "" in that case, which may not be the desired result.


If you're going to write a completely bullet-proof routine, you need also to check that the incoming arguments are not in an unassigned state. Depending on how you like to cast the logic, use either the Assigned or the UnAssigned function to test.