[GIS] Determining Min/Max values from feature class using ArcPy

arcgis-10.2arcpycsvexport

I am very rusty/inexperienced in Python.

I would like to create a more compact script that prints min and max values of each numeric field from a feature class. Right now I have the code below repeated for each field that contains numeric values.

How would I code this to identify if a field has numeric values and then print the min and max values to the python shell or even better to a .csv/text file?

import arcpy
data = "C:/Workfolder/Input.gdb/FeatureClass"

listname = []
cursor = arcpy.da.SearchCursor(data, "field1")

for row in cursor:
    listname.append(int(row[0]))

print 'Field1_min, {0}'.format(min(listname))
print 'Field2_max, {0}'.format(max(listname))

Best Answer

I think one of the efficient options would be using where and sql_clause arguments of arcpy.da, for example:

field_to_find_min_max = "MyFieldName"
min_value = arcpy.da.SearchCursor(data, field_to_find_min_max, "{} IS NOT NULL".format(field_to_find_min_max), sql_clause = (None, "ORDER BY {} ASC".format(field_to_find_min_max))).next()[0]
max_value = arcpy.da.SearchCursor(data, field_to_find_min_max, "{} IS NOT NULL".format(field_to_find_min_max), sql_clause = (None, "ORDER BY {} DESC".format(field_to_find_min_max))).next()[0]

This also makes sure the only non-NULL values are processed (where clause).

Related Solutions

[GIS] Extracting data using arcpy.da.SearchCursor

You need to grab the first element of each row and convert to int.

listname = []
cursor = arcpy.da.SearchCursor(fires, "YYYYMMDD")

for row in cursor:
    listname.append(int(row[0]))

print 'the first fire date is {0}.'.format(min(listname))
print 'the last fire date is {0}.'.format(max(listname))

[GIS] Search Cursor Return Field Name If All Rows Contain a Value

The most efficient way to do it (i.e., not reading every single row in the table) is to do this...see the comments for explanation:

import arcpy
fiberCable = r'Orlando\Orlando_FIM_prep\FIBERCABLE'
field = "inventory_status_code"
# Go ahead and put the field name into the output list
output_fields = [field]
# Compose a where clause to limit the cursor to iterate over records where the field is null
where_clause = '{} IS NULL'.format(field)
with arcpy.da.SearchCursor(fiberCable, field, where_clause) as cursor:
     # If any records are null, remove the field name from the output list and then break out of the loop.
     for row in cursor:
         output_fields.remove(field)
         break

Assuming that you want to do this for multiple fields:

import arcpy
fiberCable = r'Orlando\Orlando_FIM_prep\FIBERCABLE'
fields = ["inventory_status_code", 'another_field_name']
output_fields = list()
for field in fields:
    output_fields.append(field)
    where_clause = '{} IS NULL'.format(field)
    with arcpy.da.SearchCursor(fiberCable, field, where_clause) as cursor:
         for row in cursor:
             output_fields.remove(field)
             break

By the way, never ever ever use a python keyword of any kind as a variable name (e.g., list)

Best Answer

Related Solutions

[GIS] Extracting data using arcpy.da.SearchCursor

[GIS] Search Cursor Return Field Name If All Rows Contain a Value

Related Question