I have a float field which I want to simply update all values with 1. I can easily do this within the field calculator but I have started using python today, what is the syntax to simply update a field with the value 1. I'm stuck on the expression bit of the script:


1 Answer 1


Looking at the ArcGIS help section, you can see the necessary parameters and descriptions:

CalculateField_management (in_table, field, expression, {expression_type}, {code_block})

To translate this to your script;

import arcpy

file = r'C:\your\file.shp'

arcpy.CalculateField_management (file, "FRMEAS", "1")
  • Thanks, I was thinking into it to much by doing =1 or "!FRMEAS! = 1"
    – Alan Carr
    Apr 3, 2014 at 16:10
  • @Aaron if it's a float field, do you have to put the 1 in quotes?
    – ianbroad
    Apr 3, 2014 at 16:12
  • 1
    It is optional @ian
    – Aaron
    Apr 3, 2014 at 16:16

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