ArcGIS Calculate Value tool - Python syntax error

Question

I have a feature class within a file geodatabase.

I am using the "Iterate row selection" iterator in Model Builder to read each row in the FC. I am then using the "Get Field Value" tool to read the following 3 fields from each row:

"Status"

"User"

"Tile"

I then want to use the "Calculate Value" tool to return a string, which I will later use as a file path to copy a specific file. The logic is as follows: If "Status" is "Available", return C:\Data\ + "Tile" otherwise return C:\Data\ + "Tile" + _ + "User"

In the Calculate Value tool, I've put the following into the expression field:

a("%Status%", "%User%", "%Tile%")

I've put the following into the Code Block:

def a(Status, User, Tile):
 if Status == "Available":
 return "C:\Data\" + Tile
 else:
 return "C:\Data\" + "Tile" + "_" + User

I have the "Data type" set as string.

My model is as follows:

enter image description here

I get the following error for my code block:

 ERROR 000989
Python syntax error: Parsing error SyntaxError: EOL while scanning string literal (line 3)

I'm happy to have a solution using model builder or using a stand along python script.

Answer 1

You should escape the \ character, this way:

def a(Status, User, Tile):
 if Status == "Available":
 return "C:\\Data\\" + Tile
 else:
 return "C:\\Data\\" + "Tile" + "_" + User

• mr.adam: yeah, or other options: 1. r"C:\data\" + Tile 2. r"C:\"Data"\{0}".format(Tile)
• Jason Scheirer: @mr.adam r'c:\data\' is still a syntax error. Raw strings that end with a backslash still need the final backslash to be represented as `\`
• mr.adam: @JasonScheirer ah, thanks for pointing that out. Double slashes would be good here then.

Answer 2

The problem, as indicated in gcarillo's answer, are the single \ characters, specially before the closing quote.

Some solutions:

• Use / instead of \. Windows normally uses backslashes, but forward slashes work too except in the command prompt (cmd.exe).
• Raw strings can be useful, but they don't help with strings that end in a backslash.
• My favorite solution in cases like this: use os.path.join() instead of hardcoded path delimiters.

Example using os.path.join():

import os.path
def a(Status, User, Title):
 if Status == "Available":
 return os.path.join("C:", "Data", Tile)
 else:
 return os.path.join("C:", "Data", "Tile_" + User) # Or did you mean os.path.join("C:", "Data", Tile + "_" + User) ?