How to replace null values in attribute table ArcGIS 10.2

An automated way of doing this task is running a python function within Field Calculator (no selecting and reverse selecting required), see example below:

Additionally, if you wanted to replace NULL with an empty string just add these two statements:

elif value is None:
    return ''

Here is how I would do this:

1. Select all rows where oneway = "+" then run a field calculate to set them to "F"
2. Select all rows where oneway = "-" then run a field calculate to set them to "T"
3. Select all rows where oneway = "F" AND oneway = "T", reverse the selection then run the field calculate and set remaining rows to "null".

I had this problem after having done a spatial join - I had null value which in my case needed to changed to 0. I solved it using the following method:

• Toolbox 'Table Select' (This extracts all the Fields to a table)

• Toolbox 'Table to Excel'

• I then opened the resulting Excel file in Excel and using Replace, replaced [Blank] with 0. You then need to format the cells, cell with numbers in them need to be formatted as numbers and text as text etc.

• Toolbox 'Excel to Table' (All the null values are now 0).

• Join by attributes to the original feature.

It all worked very well! (Sometimes it is much easier to do things in other programs!)