arcpy – Calculating Statistics Across Multiple Fields in arcpy

arcpystatistics

The summary statistics command can be used in arcpy to calculate statistics – this tool runs against a single field, eg:

SUM—Adds the total value for the specified field.

Is there an out-of-the-box method to calculate statistics across multiple fields?

eg I'd like to calculate the MIN, MAX, MEAN and STDEV of Field1, Field2 and Field3, combined:

OID  Field1  Field2 Field3 Field4
 1     23      24     25     26
 2     12      13     14     15
 3     17      18     19     20

One approach is to read through the table with a cursor, and calculate these values manually in a script. Is there a better/faster way?

Edit: I need this to run on only the selected records, and these will change frequently.

Best Answer

Your best bet for this approach would definitely be a cursor. You can create a python tool that takes 2 inputs:

  • Feature class/table in question
  • multi-value parameter for all the fields you are interested in

The code to grab all this information is pretty straightforward:

import math, itertools, arcpy

FC = arcpy.GetParameterAsText(0)
fields = arcpy.GetParameterAsText(1).split(";")

#Flatten a list of lists
def flatten(list_lists):    
    return list(itertools.chain.from_iterable(list_lists))

#Whatever standard dev func is applicable
def std(x):
    pass

#read values from fields and flatten
vals = flatten([r for r in row] for row in arcpy.da.SearchCursor(FC, fields))

arcpy.AddMessage("\nThe MIN is: {}".format(min(vals)))
arcpy.AddMessage("The MAX is: {}".format((max(vals))))
arcpy.AddMessage("The MEAN is: {}\n".format(sum(vals) / len(vals)))
arcpy.AddMessage("The STD is: {}".format(std(vals)))

If you want to dump the statistics to a table with a timestamp, that can be easily accomplished.

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