# How To Determine Percent of Matched Data?

In my attribute table, I have 2 columns with qualitative (categorical) data. Both of them are from different sources so I am trying to find the percent of matched data from these 2 columns. I created a new column labeled 'Matched', and wrote the following codeblock in the Field Calculator to determine the values, but I am getting an error on line 2-3. Do I have to convert them to string using `str()`?

``````def matchedRecords(x):
x = (column.name)
x2 = (column2.name)

if x == x2:
resultIs = "Matched"
else:
resultIs = "Unmatched"
return resultIs
``````

And then `matchedRecords(!Matched!)` in the second area of the Field Calculator. I want to determine the total matched values versus unmatched values to find the percentage. Is this the best way to do it? Thanks.

• The simplest way is to compare the record count to the selection count when selecting all records with a match (which is a simple query requiring no table calculations). Jan 13, 2014 at 18:00
• You're right. This was much simpler. Thank you for your help. Just ran a query to select the records that are equal in both columns. Jan 13, 2014 at 18:55

I think the logic is incorrect for what you are trying to accomplish. I believe you need to pass the first two columns in the function:

``````def matchedRecords(A, B):
if A == B:
results = "Matched"
else:
results = "Unmatched"
return results
``````

Then in the field calculator for the Matched field:

``````matchedRecords(!column1!, !column2!)
``````

This is untested, but should work. Once you have the number (count) of matched vs unmatched, you can calculate a percentage.

• This worked, as did the query method suggested by whuber. Thank you! Jan 13, 2014 at 18:56
• Yes, whuber's solution is much easier Jan 13, 2014 at 20:05

You can obtain the number of matching feature after selecting the feature where both fields are equal in the attribute table.

Selection > select by attribute, using the following SQL statement

[fieldA] = [fieldB]

then you can read the number of selected features at the bottom of your attribute table (see image) or when you use the selection snippet in the table of content.