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The ArcPy layer.labelClasses.expression method does not accept properly formatted strings if they contain multiple quotation marks.

Last Published: June 24, 2015 ArcGIS for Desktop
Bug ID Number BUG-000088225
SubmittedJune 9, 2015
Last ModifiedNovember 24, 2020
Applies toArcGIS for Desktop
Version found10.3.1
StatusWill Not Be Addressed

Additional Information

This is a known behavior. The additional quotes are needed to make sure the Python window reads the field 'FID' and not a variable in a list.


The additional quotes are needed to properly form the string to be set as the expression. Without them it will not read 'FID' as a field. Instead, the method inteprates as the user is trying to use a variable in a list, because that is what that means in a Python interpreter. In the expression dialog, it does not expect the additional quotes because the Python parser understands that the brackets around a word indicate a field. Use triple quotes around the expression to maintain the full string: layer.labelClasses[0].expression = ''' "<CLR red='255'><FNT size = '17'>" + [OBJECTID] + "</FNT></CLR>" '''

Steps to Reproduce

Bug ID: BUG-000088225


  • ArcGIS for Desktop

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