English

How To: Create sequential numbers in a field using Python in the Field Calculator

Summary

Instructions provided describe how to create sequential numbers in a field using Python in the Field Calculator.

Procedure

Note:
The code in this article generates sequential numbers for unsorted data based on the OID or FID order. If the data is sorted on a field, the generated numbers will not be sequential.
  1. Create a new short integer field.
  2. Right-click the new field and select Field Calculator.
  3. Set the Parser to Python.
  4. Check the check box for Show Codeblock.
  5. Paste the following into the Pre-Logic Script Code:
    rec=0 
    def autoIncrement(): 
     global rec 
     pStart = 1  
     pInterval = 1 
     if (rec == 0):  
      rec = pStart  
     else:  
      rec += pInterval  
     return rec
  6. Paste the following code in the smaller box below the Pre-Logic Script Code:
    autoIncrement()
  7. Click OK. The following image is an example of a field with sequential numbers populated using the Python code:
    An image of a field with sequential numbers.

Related Information