I have a lot of rows of data, and I want to use the field calculator to give a uniform assignment of


but I don't know how to implement it.

Can someone help me?

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  • You could look at the Python modulo operator of % – PolyGeo Apr 8 '18 at 4:55
  • @Polygeo it will always work on shapefile (FID), not necessarily on features in database. – FelixIP Apr 8 '18 at 4:59

Use this advanced field calculator expression (Python):

def switch():
 global i
 return i
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As @PolyGeo mentioned, the modulo operator helps you determine whether a number is pair or not. You can check the "Show Codeblock" box in the field calculator and then write a simple function that determines wheter the row is pair or not and adds a 0 or a 1 depending on the condition

def calc(fid):
    if fid % 2 != 0:
        return 0
        return 1

Then, in the box under you jsut have to call the function using the FID field as an argument.

calc( !FID! )

Note: make sure python is checked as the parser.

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  • 3
    Why bother with advanced expression if simple !FID!%2 solves it for shapefile? – FelixIP Apr 8 '18 at 5:02
  • I understand this idea, but I use it to achieve, there will be mistakes.I use the previous method can be achieved. – Girl Apr 8 '18 at 5:16

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