Writing ArcMap Label Expression in VBscript?

Question

I have to columns, pipe material and pipe size, I only want to label pipes with a size greater than 2"

I am trying to do this but keeps kicking back and error, can anyone assist in what im doing wrong?

Function FindLabel ( [PIPE_MATERIAL] , [PIPE_INTERNAL_DIAMETER] )
 if ( [PIPE_INTERNAL_DIAMETER] > 2") then
 FindLabel = [PIPE_MATERIAL] 
 end if
End Function

Answer 1

Function FindLabel ( [PIPE_MATL], [PIPE_DIA] )
 ' this just pulls first digit from PIPE_DIA string 2", 3" & converts to Double type - you may have to play around with... 
 If CDbl( Mid([PIPE_DIA], 1, Len([PIPE_DIA])-1)) > 2 then
 FindLabel = [PIPE_MATL]
 else 
 FindLabel = ""
 end if
End Function

Adding unit decorations to a data field (like inch marks etc.) is always a BAD idea, poor database structure. The reason your code fails is your mixing data types in your "If" statement. You need to compare either 'all string' or 'all number' types.

• Pob 1: cm1 - great that worked! Thanks alot! PS) The dataset was inherited from someone else I didnt create it.
• cm1: Great! If CDbl( Mid([PIPE_DIA], 1, Len([PIPE_DIA])-1)) > 2 then is probably better than If CDbl(Mid([PIPE_DIA], 1, 1))> 2 then I fully understand inheriting 'data badness'... good luck.
• Pob 1: You read my mind, I was just going to respond with it only showing sizes below double figures, but that follow up solved it :) many thanks again!

Answer 2

I think it must be near your 'if ( [PIPE_INTERNAL_DIAMETER]> 2") then' line.

Your wanting to perform a logical mathematical operation there and the double quote after the 2" is probably getting in the way - getting interpreted as a string.

if PIPE_INTERNAL_DIAMETER is an integer field then you need to do something like:

Function FindLabel ( [PIPE_MATL], [P_INT_DIAM] )
if ( [P_INT_DIAM] > 2) then
 FindLabel = [PIPE_MATL]
end if
End Function

• Pob 1: Hi, I tried adjusting it to Function FindLabel ( [PIPE_MATERIAL] , [PIPE_INTERNAL_DIAMETER] ) if ( [PIPE_INTERNAL_DIAMETER] > 2) then FindLabel = [PIPE_MATERIAL] end if End Function but still kicks back an error, the data type is double if that makes a difference
• cm1: What's the error message returned when you click the 'Verify' button?
• Pob 1: also it might be worth mentioning to you, that the pipe internal diameter columns actually have that unit value in them " ie inches 6" 4" 8" etc, is that gonna confuse things or is it still viable?
• Pob 1: The expression contains an error. Modify the expression and try again. Error 13 on line 2. Type mismatch: esri__1'.
• kenbuja: Try using single quotes: if ( [PIPE_INTERNAL_DIAMETER] > '2"' ) then

Answer 3

I'm not really good with VB, so I'll offer a Python attempt. You would need to change from the Visual Basic parser to the Python parser and give something like this a try:

def FindLabel ( [PIPE_MATL], [PIPE_DIA] ):
 # assign pipe diameter string to S
 S = [PIPE_DIA]
 # trim the double-quote character from the end of the diam string/chg to float variable
 if (float(S[:-1]) > 2.0):
 return [PIPE_MATL]
 else:
 return ''

Be sure to keep the indentations intact if you cut-&-paste this. Whitespace/indentation is important/means 'run this block of code together' to Python.

• Pob 1: Im running 10.0 the only parser options I have is Jscript & vb :(