I am trying to remove extra spaces from values in a field programatically using a python script. This is the script I'm using:

field1 = "FULLST_NAME"
calc1 = "s.join(!" + field1 + "!.split())"
s = "\' \'"
arcpy.CalculateField_management(c_lines, field1, calc1, "PYTHON_9.3")

The expression used in calc1 works fine when I manually input it in the field calculator, i.e.

"   S STATE    ROUTE " is changed to "S STATE ROUTE"

However, when executing the script, it outputs:


with the ' ' between each string. I'm guessing there is some syntax I'm missing when storing the calculation in the variable and using it as a parameter in CalculateField_management(). How can I fix this?

  • split() returns a list, this is why it is happening. Have a look at the trim() method. – Hornbydd Jan 28 '17 at 0:05
  • Actually, it's happening because of how s is defined. Just plain s = " " will work. – Paul Jan 28 '17 at 0:18

When writing expressions for field calculator that perform string operations, I find it simpler to use triple-quoted strings. It can be tricky to escape otherwise (or, as you tried, you need to use variable substitution, which is strange).

field1 = "FULLST_NAME"
calc1 = """
' '.join(!{}!.split())

arcpy.CalculateField_management(c_line, field1, calc1, "PYTHON_9.3")

This is a fairly simple operation, but once you start using code blocks, cursors really shine:

with arcpy.da.UpdateCursor(c_line, field1) as cursor:
    for row in cursor:
        row[0] = " ".join(row[0].split())
  • Minor error, I think you meant to define field1 on the 1st line, otherwise the format function will err as undefined var. Otherwise, +1 for showing the updatecursor means of doing this. – T. Wayne Whitley Jan 28 '17 at 0:27
  • This did the trick!. – Andy Fisher Jan 30 '17 at 20:19

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