Modifying label string using Python label expression

Question

I'm attempting to modify my feature labels such that the "NB", "SB", "WB", and "EB" portion of the string is removed:

E.g. "CEDAR AVE NB" --> "CEDAR AVE" or "ROBERT TRL S SB" --> "ROBERT TRL S"

The code I have so far is as follows (I am new to coding):

def FindLabel([StreetName]):
    L = [StreetName]
    L1 = L.split(" ")
    if len(L1)["NB", "SB", "WB, "EB"] in L1
        return L1[0] + " " + L1[1]
    L1 = L
    FindLabel = L

Would anyone be able to provide help? In the script, I'm looking to utilize the split method, len function and in keyword in order to break up the string into word parts, return the number of items in the string and check if the values "NB", "SB", "WB", or "EB" are present in the string, respectively.

Answer 1

This approach checks the last 'word' in your string to see if it matches one of the strings you want to eliminate:

def FindLabel ([StreetName]):
    input_string = [StreetName]
    split_string = input_string.split()
    if split_string[-1] in ["NB", "SB", "EB", "WB"]:
        return " ".join(split_string[:-1])
    else:
        return input_string

Answer 2

I don't know much about Arcmap syntax for label expressions, but using Python, you could do something like:

def FindLabel ([StreetName]):
    import re
    input_string = [StreetName]
    # Regular expression that look for strings ending with a space character
    # followed by either NB, SB, EB or WB, and replace this part by an empty string
    return re.sub("\s*[NSEW]B$", "", input_string)

That is, assuming you can import modules like re

Otherwise, you can use the following snippet

def FindLabel ([StreetName]):
    input_string = [StreetName]
    for ending in (" NB", " SB", " EB", " WB"):
        if input_string.endswith(ending):
            return input_string[:-len(ending)]
    return input_string