2

I am having an issue with a simple python snippet.

Here's the background: I wanted to include an additional step in a nightly update script that replaces characters in a field that simply do not play nice with a web application that allows users to query the data. These characters included angle brackets ("<" and ">") which I was trying to replace with "Less Than" and "Greater Than".

So when I was testing the Field Calculation, I finally got it to work the way I wanted to, and as I have done with so many other snippets, I simply copied the Python Snippet of the geoprocess, and pasted into my script.

Below is the snippet:

arcpy.CalculateField_management("path/to/my/layer","field","RemoveBad( !field!)","PYTHON_9.3","def RemoveBad(x):/n   x = x.replace(\"<=\", \" Less Than or Equal To \" )/n   x = x.replace(\">=\", \" Greater Than or Equal To \")/n   x = x.replace(\"<\", \" Less Than \")/n   x = x.replace(\">\", \" Greater Than \")/n   x = x.replace(\"=\", \" Equal To \")/n   x = x.strip()/n   return x")

Now in my script, I do have a log that reports geoprocessing errors, so when I run the script, I am getting the following:

Executing: CalculateField path\to\my\layer field RemoveBad( !field!) PYTHON_9.3 "def RemoveBad(x):/n   x = x.replace('<=', ' Less Than or Equal To ' )/n   x = x.replace('>=', ' Greater Than or Equal To ')/n   x = x.replace('<', ' Less Than ')/n   x = x.replace('>', ' Greater Than ')/n   x = x.replace('=', ' Equal To ')/n   x = x.strip()/n   return x"
Start Time: Mon Aug 25 09:35:32 2014
Failed to execute. Parameters are not valid.
ERROR 000989: Python syntax error: Parsing error SyntaxError: invalid syntax (line 1)
Failed to execute (CalculateField).
Failed at Mon Aug 25 09:35:32 2014 (Elapsed Time: 0.00 seconds)

So I started combing through the script but I cannot find the issue, which leads me to believe it has something to do with the angle brackets.

To reiterate, this python snippet is from a successful Field Calculator geoprocess.


Per Alex's feedback I created the following variable:

RemoveBad = """def RemoveBad(x):
   x = x.replace(\"<=\", \" Less Than or Equal To \" )
   x = x.replace(\">=\", \" Greater Than or Equal To \")
   x = x.replace(\"<\", \" Less Than \")
   x = x.replace(\">\", \" Greater Than \")
   x = x.replace(\"=\", \" Equal To \")
   x = x.strip()
   return x"""

Then I updated the snippet:

 arcpy.CalculateField_management("path/to/my/layer","field","RemoveBad( !field!)","PYTHON_9.3",RemoveBad)

The error is now gone and script is working as expected.

6

Try adjusting your code, your /n should be \n:

arcpy.CalculateField_management("path/to/my/layer","field","RemoveBad( !field!)","PYTHON_9.3","def RemoveBad(x):\n   x = x.replace(\"<=\", \" Less Than or Equal To \" )\n   x = x.replace(\">=\", \" Greater Than or Equal To \")\n   x = x.replace(\"<\", \" Less Than \")\n   x = x.replace(\">\", \" Greater Than \")\n   x = x.replace(\"=\", \" Equal To \")\n   x = x.strip()\n   return x")

Or better yet, put your code block in a triple-quoted string so you can read it (and you don't need to escape your quotes):

arcpy.CalculateField_management("path/to/my/layer",
                                "field",
                                "RemoveBad(!field!)",
                                "PYTHON_9.3",
                                """def RemoveBad(x):
   x = x.replace("<=", " Less Than or Equal To " )
   x = x.replace(">=", " Greater Than or Equal To ")
   x = x.replace("<", " Less Than ")
   x = x.replace(">", " Greater Than ")
   x = x.replace("=", " Equal To ")
   x = x.strip()
   return x""")

and if you'd rather do it as a cursor:

def fixvalue(val):
       return (val.replace("<=", " Less Than or Equal To " )
                  .replace(">=", " Greater Than or Equal To ")
                  .replace("<", " Less Than ")
                  .replace(">", " Greater Than ")
                  .replace("=", " Equal To ")
                  .strip())

with arcpy.da.UpdateCursor('path/to/my/layer', "field") as cur:
    for row in cur:
        row[0] = fixvalue(row[0])
        cur.updateRow(row)

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