Replace Multiple Values in an Attribute Table Field using Field Calculator

RebeccaLeach · ‎10-27-2017

I'm new to python and trying to write a python script using the field calculator in ArcMap for a specific field in an attribute table that will replace some of the values in the field but leave the other values as they are within the table. For example: ""fourth" must be changed to "4th" whereas "Neilston" should remain as it is in the field. The field in the table looks like this:

The python script used in the codeblock looks like this:

def streetNUM(field):

if field == "Fourth":

field.replace ("Fourth","4th")
elif field == "Fifth":

field.replace ("Fifth","5th")
else:
return field

And then in the box below the codeblock I have:

streetNUM(!FULLNAME!)

Nothing seems to change and I get an error code saying "Field is not nullable [FULLNAME]". Any suggestions as to where I may be going wrong with my code?

JasonBalmut · ‎07-02-2019

Thank you for the dictionary solution to this common issue, Xander Bakker. I have a similar question for parsing road names along with their suffixes and translating them to MSAG values. Interstates, County Roads, and State Roads follow a different pattern to our normal street names:

def translateNAME(streetName, dirSuf):
	dctSTREETNAME = {"Interstate ": "I", "US Highway": "", " US Highway": "", "Martin Luther King Jr": "Dr King", "Saint": "St", "County Road ": "", "State Road ": ""}
	for findSTREETNAME, replaceMSAGNAME in dctSTREETNAME.items():
		if 'Interstate' in streetName and 'N' in dirSuf:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME) + ' Northbound'
		elif 'Interstate' in streetName and 'S' in dirSuf:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME) + ' Southbound'
		elif 'Interstate' in streetName and 'E' in dirSuf:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME) + ' Eastbound'
		elif 'Interstate' in streetName and 'W' in dirSuf:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME) + ' Westbound'
		elif 'County Road' in streetName or 'State Road' in streetName:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME) + ' Hw'
		else:
			streetName = streetName.replace(findSTREETNAME, replaceMSAGNAME)
	return streetName.strip()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

When I run this script the normal streets are correct, but I get repeating concatenations for the others.

Any thoughts on how to fix this?

XanderBakker · ‎07-02-2019

Hi jesterjace ,

You have your replace statements inside the loop, so it gets applied multiple times. I can't reproduce the same result as you have with many "Hw" in the resulting name, but maybe you should try something like this:

def translateNAME(streetName, dirSuf):
    dctSTREETNAME = {"Interstate ": "I",
                  "US Highway": "",
                  "Martin Luther King Jr": "Dr King",
                  "Saint": "St",
                  "County Road ": "",
                  "State Road ": ""}
    result = streetName
    for findSTREETNAME, replaceMSAGNAME in dctSTREETNAME.items():
        result = result.replace(findSTREETNAME, replaceMSAGNAME)

    if 'Interstate' in streetName and 'N' in dirSuf:
       result += ' Northbound'
    elif 'Interstate' in streetName and 'S' in dirSuf:
       result += ' Southbound'
    elif 'Interstate' in streetName and 'E' in dirSuf:
       result += ' Eastbound'
    elif 'Interstate' in streetName and 'W' in dirSuf:
       result += ' Westbound'
    elif 'County Road' in streetName or 'State Road' in streetName:
       result += ' Hw'
    return result.strip()‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I haven't tested the code though...

JasonBalmut · ‎07-03-2019

Perfection! Thanks, Xander Bakker‌!