topic Passing parameters to the featureLayer.calculate in ArcGIS API for Python Questions

Passing parameters to the featureLayer.calculate

ChuckBenton — Thu, 12 Aug 2021 18:41:28 GMT

I'm sure this is a simple issue, but it's stumped me.

The following line executes without issue:

fs_layer.calculate(where="FIPS=18039", calc_expression={"field":"VERSION", "value": "07/04/2021"})

This fails:

where_str = '"FIPS=18039"'
calc_str = '"field":"VERSION", "value":"07/10/2021"'
fs_layer.calculate(where=where_str, calc_expression={calc_str})

Ultimately I want to iterate the fs_layer.calculate line in a loop, passing different FIPS and VERSION values each time.

I've tried multiple ways to build the parameters to be passed, building the entire argument, varying quote schemes, and so on. What am I missing?

Re: Passing parameters to the featureLayer.calculate

DavidPike — Thu, 12 Aug 2021 19:06:44 GMT

just as you might have a string going to a string within a list, the quotes aren't removed. e.g.

my_string = 'a' my_list = [my_string] # so my_list looks like ['a'], not [a] my_string = "I've made a string" my_list = [my_string] #...

containing the string in curly braces acts in the same way as the list forcing, calc_expression just becomes a set containing the string.

Re: Passing parameters to the featureLayer.calculate

ChuckBenton — Thu, 12 Aug 2021 19:24:48 GMT

This doesn't seem to be the issue. I've converted to lists and run the following:

where_str = '"FIPS=18039"'
where_list = [where_str]
calc_str = '"field":"VERSION", "value":"07/10/2021"'
calc_list = [calc_str]
print("where="+where_list[0]+", calc_expression={"+calc_list[0]+"}")
fs_layer.calculate(where=where_list[0], calc_expression={calc_list[0]})

I added the print line to confirm formatting, its output:

where="FIPS=18039", calc_expression={"field":"VERSION", "value":"07/10/2021"}

I get the same error as when I passed the strings:

Exception: 
Invalid parameters
(Error Code: 400)

Keep in mind this line works:

fs_layer.calculate(where="FIPS=18039", calc_expression={"field":"VERSION", "value": "07/04/2021"})

I'm still stumped....

Re: Passing parameters to the featureLayer.calculate

DavidPike — Thu, 12 Aug 2021 20:30:26 GMT

Forget about the list, it's just an example of what's going on. When printing calc_expression, it looks like a dictionary but it's not - it's still a string. Check this by using the type() method - e.g. print(type(calc_expression))

you'll see the one which works is a dict, the other is either a set or a string.

What's the purpose of trying to use the first method to create the dictionary?

Re: Passing parameters to the featureLayer.calculate

ChuckBenton — Thu, 12 Aug 2021 22:06:50 GMT

What I need is a generic function I can call, passing it a FIPS and date (both as strings). I have about 150M records, spread among about 2000 distinct FIPS values, for which I want to update the VERSION fields. Something like

def updateRecords(fips, version_date)

fs_layer.calculate(where=fips, , calc_expression={"field":"ATTDATE", "value": version_date})

Of course, passing the parameters to work within .calculate is the issue. As you've probably guessed, I'm not a Python expert!

Thanks in advance for your advice!

Re: Passing parameters to the featureLayer.calculate

DavidPike — Thu, 12 Aug 2021 22:26:01 GMT

ok so you just need to construct a dictionary with the function.

def updateRecords(fips, version_date): calc_dict = {} calc_dict['field'] = 'ATTDATE' calc_dict['value'] = version_date fs_layer.calculate(where=fips, , calc_expression=calc_dict)

Re: Passing parameters to the featureLayer.calculate

ChuckBenton — Thu, 12 Aug 2021 23:45:52 GMT

Thanks so much! Still struggling with one last detail.

def updateRecords(fips, version_date):
fips = '"FIPS=' +fips+'"'
print(fips)
calc_dict = {}
calc_dict['field'] = 'VERSION'
calc_dict['value'] = '"' + version_date + '"'
fs_layer.calculate(where=fips, calc_expression=calc_dict)

The print statement yields

"FIPS=06007"

but I get

Exception: 
'where' parameter is invalid
(Error Code: 400)

Change the last line to

fs_layer.calculate(where="FIPS=06007", calc_expression=calc_dict)

and all works.

I'm still missing something that's not jumping out to me.

Thanks again for helping a newbie!

Re: Passing parameters to the featureLayer.calculate

DavidPike — Fri, 13 Aug 2021 00:08:39 GMT

not sure if FIPS is a string or Int, I'll assume its a string from your code

fips = '"FIPS" = "{0}"'.format(fips)

Re: Passing parameters to the featureLayer.calculate

ChuckBenton — Mon, 16 Aug 2021 13:03:28 GMT

Still didn't do the trick.

fips = '"FIPS={0}"'.format(fips) yields

"FIPS" = "06007"

from the print, and

Exception: 
'Invalid field: 06007' parameter is invalid
(Error Code: 400)

for the error.

Suggestions?

Re: Passing parameters to the featureLayer.calculate

DavidPike — Mon, 16 Aug 2021 13:41:53 GMT

I don't know your data types. I've gone over what you previously have said has worked, and although I don't entirely understand the leading 0 and it not being a string, this will probably work:

"FIPS={0}".format(fips)

Re: Passing parameters to the featureLayer.calculate

ChuckBenton — Mon, 16 Aug 2021 13:59:23 GMT

That did it. Thanks!!