How to access just one specific value in a row

Question

I am looking for a way to compare  values in my fieldA. Specifically I would like to compare my last value to the one in the row above. I used GetCount to know how many rows I have. So for example if GetCount returns that there is 10 rows, I would like to compare numeric values from row 10 and 9 in a fieldA. For some reason I have problem with accessing values with a specific index: I can access all values but not just one. I tried to modify code from http://resources.arcgis.com/en/help/main/10.1/index.html#//002z0000001q000000

with arcpy.da.SearchCursor(fc, ['fieldA',]) as cursor:
    for row in cursor:
        print(row)

to something like

with arcpy.da.SearchCursor(fc, ['fieldA',]) as cursor:
    for row in cursor:
        myValue=row[10]
print (myValue)

but it does not work.
Did anybody figured out how to access just one specific value, not all of them?

benberman · Answer

something like this:

list =sorted([row.getvalue(fieldname) for row in arcpy.SearchCursor(inputdata,query...fields,sort)])
print list[-2:]

T__WayneWhitley · Answer

yep, ye ol' list comprehension, certainly worth a vote!  Personally, I would have preferred compiling a dictionary to have a key lookup for any value I like, ah but this user needs to learn how to fish 1st, what do you think?

Happy Friday, Chris!

PS- my 1000th post, for what that is worth!

ChrisSnyder · Answer

How about:

listOfFieldValues = [r[0] for r in arcpy.da.SearchCursor(myTbl, ["FieldA"])]
numberOfFieldValues = len(listOfFieldValues)
lastFieldValue = listOfFieldValues[-1]
secondToLastFieldValue = listOfFieldValues[-2]