ArcGIS Help 10.1 - Frequency (Analysis)

Summary

Reads a table and a set of fields and creates a new table containing unique field values and the number of occurrences of each unique field value.

Usage

The output table will contain the field Frequency and the specified frequency field(s) and summary field(s).
The output table will contain the frequency calculation for each attribute value combination of the specified frequency field(s).
If a summary field is specified, the unique attribute values of the frequency calculation are summarized by the numeric attribute values of each summary field.
When using layers, only the currently selected features are used in calculations.

Syntax

Frequency_analysis (in_table, out_table, frequency_fields, {summary_fields})

Parameter	Explanation	Data Type
in_table	The table containing the field(s) that will be used to calculate frequency statistics. This table can be an INFO or OLE DB table, a dBASE or a VPF table, or a feature class table.	Table View; Raster Layer
out_table	The table that will store the calculated frequency statistics.	Table
frequency_fields [frequency_fields,...]	The attribute field or fields that will be used to calculate frequency statistics.	Field
summary_fields [summary_fields,...] (Optional)	The attribute field or fields to sum and add to the output table. Null values are excluded from this calculation.	Field

Code Sample

Frequency Example (Python Window)

The following Python window script demonstrates how to use the Frequency function in immediate mode.

import arcpy
arcpy.env.workspace = "C:/data/Portland.gdb/Taxlots"
arcpy.Frequency_analysis("taxlots",
                         "C:/output/output.gdb/tax_frequency",
                         ["YEARBUILT", "COUNTY"],
                         ["LANDVAL", "BLDGVAL", "TOTALVAL"])

Frequency Example 2 (stand-alone script)

The following stand-alone script demonstrates how to use the Frequency function.

# Name: Frequency_Example2.py
# Description: Run Frequency on a table
 
# Import system modules
import arcpy
 
# Set environment settings
arcpy.env.workspace = "C:/data/Portland.gdb/Taxlots"
 
# Set local variables
inTable = "taxlots"
outTable = "C:/output/output.gdb/tax_frequency"
frequencyFields = ["YEARBUILT", "COUNTY"]
summaryFields = ["LANDVAL", "BLDGVAL", "TOTALVAL"]
 
# Execute Frequency
arcpy.Frequency_analysis(inTable, outTable, frequencyFields, summaryFields)

Frequency Example 3 (stand-alone script)

The following stand-alone script demonstrates how to use many geoprocessing scripting functions, including the Frequency function.

# Name: Frequency_Example3.py
# Description: Break all multipart features into singlepart features, 
#  and generate a report of which features were separated.
 
# Import system modules
import arcpy
 
# Create variables for the input and output feature classes
inFeatureClass = "c:/data/gdb.gdb/vegetation"
outFeatureClass = "c:/data/gdb.gdb/vegetation_singlepart"

try:
    # Create list of all fields in inFeatureClass
    fieldNameList = [field.name for field in arcpy.ListFields(inFeatureClass)]

    # Add a field to the input this will be used as a unique identifier
    arcpy.AddField_management(inFeatureClass, "tmpUID", "double")
 
    # Determine what the name of the Object ID is 
    OIDFieldName = arcpy.Describe(inFeatureClass).OIDFieldName
   
    # Calculate the tmpUID to the OID
    arcpy.CalculateField_management(inFeatureClass, "tmpUID",
                                    "[" + OIDFieldName + "]")
 
    # Run the tool to create a new fc with only singlepart features
    arcpy.MultipartToSinglepart_management(inFeatureClass, outFeatureClass)
 
    # Check if there is a different number of features in the output
    #   than there was in the input
    inCount = int(arcpy.GetCount_management(inFeatureClass).getOutput(0))
    outCount = int(arcpy.GetCount_management(outFeatureClass).getOutput(0))
    
    if inCount != outCount:
        # If there is a difference, print out the FID of the input 
        #   features which were multipart
        arcpy.Frequency_analysis(outFeatureClass,
                                 outFeatureClass + "_freq", "tmpUID")
 
        # Use a search cursor to go through the table, and print the tmpUID 
        print("Multipart features from {0}".format(inFeatureClass))
        for row in arcpy.da.SearchCursor(outFeatureClass + "_freq",
                                         ["tmpUID"], "FREQUENCY > 1"):
            print int(row[0])
    else:
        print("No multipart features were found")

except arcpy.ExecuteError:
    print(arcpy.GetMessages())
except Exception as e:
    print(e)

Environments

Output CONFIG Keyword, Current Workspace, Scratch Workspace

Licensing Information

ArcGIS for Desktop Basic: No

ArcGIS for Desktop Standard: No

ArcGIS for Desktop Advanced: Yes

5/6/2013