Calculate maximum value from a subset of fields ending with a standard suffix

Question

I'm using the Python built-in function in the calculate field tool in Modelbuilder to calculate maximum values for each record from a list of fields:

This is the field calculator expression I use in the moment: max[(!field1_abc!, !field2_abc!, !field3_abc!)]

It worked perfectly so far. But I selected the fileds that are calculated manually. So now I'd like to find a way to automate it. I'd like to calculate the maximum from all fields ends with "abc".

Is it possible to combine the built- in fuction with something like "calculate the max from all fields .endwith("abc")"?

I tried something like: max([!endswith("abc")!]) but it is not working.

Answer 1

This can be done in modelbuilder but you need to construct the expression for the calculate tool. The model is simply this:

I have a table called test and it is loaded into the map document:

Calculate Value tool is as this:

Note that I pass in the name of the table, in my case test. The code is constructing the expression that feeds into the calculate field tool expression parameter. It creates an expression choosing the max value from all fields ending with _abc. Obviously your fields need to be numeric! This code assumes that is the case.

The code block is provided below to copy:

import arcpy
def createExpression(dataset):
  l = arcpy.ListFields(dataset,"*_abc","ALL")
  sql = "max(["
  for f in l:
    sql = sql + "!" + f.name + "!" + ","
  sql = sql[:-1] + "])"
  return sql

The calculate tool is set up as:

It takes the expression built by the calculate value tool and computes the maximum value into an existing numeric field called m.

Answer 2

Please give this a try in the python console. Assuming you only have 3 fields and are putting the max value of fields in another field, so we create a max field

import arcpy

arcpy.env.workspace = (r"E:/folder1/folder2")

inputFc = "test.shp" # set to the right file
fieldList = []


#create field for max value (may not be what you want)
arcpy.AddField_management(inputFc,'MAX_abc','DOUBLE')

fields = arcpy.ListFields(inputFc)
for field in fields:
    if (field.name).endswith('abc'):
        fieldList.append(field.name)

with arcpy.da.UpdateCursor(inputFc, fieldList) as uc:
    for row in uc:
        row[3] = max(row[0], row[1], row[2])
        uc.updateRow(row)