idea Calculate statistics for selected features and pass to a variable in Python Ideas

Calculate statistics for selected features and pass to a variable

d484648 — Fri, 21 May 2021 14:15:20 GMT

The analysis.Statistics tool calculates statistics for selected rows but puts the value in a CSV table. I want to be able to calculate the sum of values in a field for selected rows and then use the sum elsewhere in my Python Script.

Re: Calculate statistics for selected features and pass to a variable

DuncanHornby — Fri, 04 Jun 2021 14:55:28 GMT

Just use a searchcursor if you want to read values from a selection, or you could call the summary statistics tool.

Re: Calculate statistics for selected features and pass to a variable

d484648 — Fri, 04 Jun 2021 16:30:05 GMT

Thanks for the reply.

The summary statistics tool generates a CSV file for each sum. I don't need that.

I'll have to look up how to read and create a running sum of values from a selection using a searchcursor.

Re: Calculate statistics for selected features and pass to a variable

MarkBryant — Wed, 04 May 2022 10:41:12 GMT

Wrap the summary statistics in a function.

def calculate_field_statistics(in_table, field, statistics_type='SUM'): """ Run the Summary Statistics on a field in a table and return the result.""" try: # Create the temporary stats result table stats_table = arcpy.CreateUniqueName('stats', 'in_memory') # The output field is statistics_type underscore field name stats_field = "{}_{}".format(statistics_type, field) # Run Summary Statistic arcpy.analysis.Statistics(in_table, stats_table, [[field, statistics_type]]) # Return the first value from the stats_table return arcpy.da.SearchCursor(stats_table, stats_field).next()[0] finally: # Delete the stats table if arcpy.Exists(stats_table): arcpy.management.Delete(stats_table)

Re: Calculate statistics for selected features and pass to a variable

d484648 — Wed, 04 May 2022 12:33:53 GMT

This is great, thanks!

Re: Calculate statistics for selected features and pass to a variable - Status changed to: Closed

ShaunWalbridge — Tue, 09 Aug 2022 20:22:56 GMT

Thanks for your idea! Based on the comments in this thread, it looks like this issue is addressable with a moderate amount of Python code directly using ArcPy, and is also possible using mechanisms like SeDF or plain pandas for performing the summarization. Based on that, will close this issue because the specific need can be addressed without a new specialized tool to solve it. Let us know if see any other areas that Python in ArcGIS can use enhancement.