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Frequency

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 for each unique 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})
ParameterExplanationData Type
in_table

The table containing the field(s) that will be used to calculate frequency statistics.

Table View; Raster Layer
out_table

The output table that will store the frequency statistics.

Table
frequency_fields
[frequency_fields,...]

The field(s) used to calculate frequency statistics. Each unique combination of field values will be included as a new row in the output table.

Field
summary_fields
[summary_fields,...]
(Optional)

The attribute field(s) to sum and add to the output table. Values will be summed for each unique combination of frequency fields. 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.

# 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.

# Description: Break all multipart features into single part 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)[0])
    outCount = int(arcpy.GetCount_management(outFeatureClass)[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 err:
    print(err)

Licensing information

  • ArcGIS Desktop Basic: No
  • ArcGIS Desktop Standard: No
  • ArcGIS Desktop Advanced: Yes

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