Python script for converting strings to numbers

EstherSullivan — Sun, 31 Jul 2011 22:02:51 GMT

I need to convert two fields entered as strings into numbers so that I can do simple arithmetic on them using the field calculator. In ArcGIS 10 Desktop, within the field calculator, what script/function should I use?

All of the posts I have read on this problem suggest scripts that are no longer in the new version of ArcGIS 10.

Re: Python script for converting strings to numbers

StacyRendall1 — Sun, 12 Dec 2021 05:30:57 GMT

If you are asking what I think you are - the answer is that you can't... As far as I know, you cannot change the type of an existing field (i.e. turning a string field into a long field)... You have to create a new field, of the desired type (i.e. long) and use the field calculator to set the new field = to the old field, Arc will handle the conversion from string to number (or whatever); then you can delete the old field. Yes, I know this is a huge pain in the ass...

If you actually meant: "how do I calculate numeric a value in Field Calculator if my inputs are text fields", then you need to do something like:

Pre-Logic Script Code:
def myFunction(input1, input2):
  Input1 = int(input1)
  Input2 = int(input2)

  # do Calculation... i.e.
  # x = 2*Input1 + 3*Input2

  # return the result of the calculation - this value is placed in the new field...
  return x

Expression:
myFunction(!input1!, !input2!)

Use int if all the input numbers are integers (that is no decimal points), or float if any of the input numbers have decimals...

topic Python script for converting strings to numbers in Python Questions

Python script for converting strings to numbers

Re: Python script for converting strings to numbers