topic Merging Strings for a new key in Geoprocessing Questions

Merging Strings for a new key

DEWright_CA — Sat, 08 Jan 2022 00:36:37 GMT

So I am updating a working in 10.8.1; before we migrate to Pro. I have a couple existing values (quarter and year_2dig) that we use. I an wanting to do something like this:

valuePrefix = "Q" + str(quarter) + str(year_2dig) + "_"

Then

arcpy.CalculateField_management(loccode_fc, "QRTR_KEY", '"valuePrefix !OBJECTID!"', "PYTHON","")

So I would have a new unique value that says Q122_1 ... etc for each row

But instead I get "colPrefix + 1" as the value... Ideas?

Re: Merging Strings for a new key

DuncanHornby — Sun, 09 Jan 2022 18:57:56 GMT

It looks like you are erroneously embedding your string within the string and using the wrong python parser,

Your code should be:

valuePrefix = "Q" + str(quarter) + str(year_2dig) + "_" arcpy.CalculateField_management(loccode_fc, "QRTR_KEY", '"' + valuePrefix + "!OBJECTID!" + '"',"PYTHON_9.3","")

Re: Merging Strings for a new key

JohannesLindner — Mon, 10 Jan 2022 08:47:08 GMT

# CalculateField can be a little hard to understand, because you have to pass # a string that evaluates to a correct Python expression. Biggest pitfall that # I see on this forum is concatenating strings, because people get mixed up # with the quotation marks of their expression and the quotation marks _around_ # the expression (that make it into a string). # It's not clear from your question where quarter and year_2dig come from, # chose the correct expression from below. Alo, note the double quotes inside # the expression and the single quotes to turn the expression into a string. # if quarter and year_2dig are fields in the table, this will result in # '"Q{}{}_{}".format(!QUARTER!, !YEAR_2DIG!, !OBJECTID!)' expression = '"Q{}{}_{}".format(!QUARTER!, !YEAR_2DIG!, !OBJECTID!)' # if quarter and year_2dig are python variables, this will result in # '"Q122_{}".format(!OBJECTID!)' expression = '"Q{}{}_'.format(quarter, year_2dig) + '{}".format(!OBJECTID!)' arcpy.CalculateField_management(loccode_fc, "QRTR_KEY", expression, "PYTHON_9.3", "")

Re: Merging Strings for a new key

JohannesLindner — Mon, 10 Jan 2022 08:53:15 GMT

valuePrefix = "Q" + str(1) + str(22) + "_" '"' + valuePrefix + "!OBJECTID!" + '"' # '"Q122_!OBJECTID!"'

That doesn't seem right.

'"' + valuePrefix + '"' + " + str(!OBJECTID!)" # '"Q122_" + str(!OBJECTID!)'

Re: Merging Strings for a new key

DEWright_CA — Tue, 11 Jan 2022 17:29:04 GMT

Perfect; so I was close; I thought it was just a mixture of the right set of quotes and double-quotes just was running out of places to try.