In ArcGIS 10.3 using the field calculator, I'm trying to concatenate a census tract field (double) with a census block field (double) into a single field that has the two values separated by a decimal point (ex: 501.3001 ) and then generate a summary table that has counts for how many times each census block occurs. I'm having trouble combining these two fields with a decimal point in between them. Should the new field be text? double? floating point?

  • The new field should be text, I wouldn't use a floating-point field to hold identification values like block and lot numbers.
    – Dan C
    Commented Mar 9, 2016 at 18:53
  • 1
    Yeah, are these tract/block ID codes, or are these values associated with tracts/blocks. Also, this feels like an XY Problem: meta.stackexchange.com/a/66378. What are you ultimately trying to accomplish?
    – Tom
    Commented Mar 9, 2016 at 18:55

2 Answers 2


Your output field should be a text field. If you set the field calculator's parser to Python, you could enter this for the formula:

'{}.{}'.format( !TractField! , !BlockField! )

If they really are double fields storing integer IDs for tracts and blocks, then enter:

'{}.{}'.format( int(!TractField!) , int(!BlockField!) )

If they are double fields storing some truly non-integer value and you want to round them to the nearest integer, use:

'{}.{}'.format( int(round(!SHAPE_Length!, 0)) , int(round(!SHAPE_Area!, 0)))

Note that if you were to set up the output field as a double/float, then you would lose any trailing zeros in your block values. 100 would become 1.

  • Great it worked I've got my new field and am able to summarize counts for each block. Thanks for the help Tom, I really appreciate it! Commented Mar 9, 2016 at 20:47

Text field should be your output field. the above answer works, another way to do this would be

  • 1
    who voted my answer down? my solution works
    – ziggy
    Commented Mar 10, 2016 at 13:46

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.