I have asked similar question at stackoverflow but posting here as well since it involves ArcGIS and python Add-In. Following code shows first step where i have to declare output folder as global so that later outputs can be saved in it as well. Right now I am getting an error at output folder string r'optfile/ras1'. Any help how to correctly store files in output folder and declare it as global would be appreciative.

import arcpy
import os
import pythonaddins

from datetime import datetime

now = datetime.now()
month = now.month
year = now.year

optfile = "C:/temp/"+str(year)+"_"+str(month)

class DrawRectangle(object):
"""Implementation for rectangle_addin.tool (Tool)"""
    def __init__(self):
        self.enabled = True
        self.cursor = 1
        self.shape = 'Rectangle'

def onRectangle(self, rectangle_geometry):
    """Occurs when the rectangle is drawn and the mouse button is released.
    The rectangle is a extent object."""

    extent = rectangle_geometry
                          "%f %f %f %f" % (extent.XMin, extent.YMin, extent.XMax, extent.YMax), 
                          r'optfile/ras1', "#", "#", "NONE")
  • The cross-posting for this has been answered on StackOverflow: stackoverflow.com/questions/14536176/… so this question should be closed.
    – blah238
    Commented Jan 27, 2013 at 9:49
  • Not exactly. Use of global variables within python Add-In is still not working. I created a new function within Add-In class to declare string and required variables as global but no avail.
    – Ibe
    Commented Jan 27, 2013 at 18:24

1 Answer 1


In the line where you call arcpy.Clip_management you reference r'optfile/ras1' which is a string, you want it to be:


so that you can make use of the variable.

  • It gave an error saying "ras1 is not defined". It worked with: optfile + '/ras1'
    – Ibe
    Commented Jan 26, 2013 at 18:42
  • 1
    @Ibe, you need to learn the difference between variables and string literals. It is a very important distinction in programming.
    – blah238
    Commented Jan 27, 2013 at 9:43
  • BTW, os.path.join(optfile,"ras1") should work presuming you want the output raster to always be named ras1.
    – blah238
    Commented Jan 27, 2013 at 9:45

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