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Frequency (Analysis) (ArcInfo only)
Release 9.2 Last modified January 13, 2009	Print all topics in : "Tools"

Related Topics

Summary Statistics (Analysis)

Creates a list of the unique code occurrences and their frequency for a specified set of items in an table.

Usage tips

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.
Current map layers may be used to define the Output Table. When using layers, only the currently selected features are used in the Frequency operation.
Learn more about working with layers and table views
The following environment setting affects this tool: Configuration Keyword.

Command line syntax
An overview of the Command Line window
Frequency_analysis <in_table> <out_table> <frequency_fields; frequency_fields...> {summary_fields; summary_fields...}

Parameter	Explanation	Data Type
<in_table>	The table containing the field(s) that will be used to calculate frequency statistics. It can be an INFO or OLE DB table, a dBASE or a VPF table, or a feature class.	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...}	The attribute field or fields that will be used to summarize the frequency results.	Field

Data types for geoprocessing tool parameters

Command line example

'  Purpose:  Determine the total amount of sales for each 
'  different customer type within each ZIP Code. 
'
'  Customer data includes customer name and address, 
'  the type of customer(restaurant, store, service station) 
'  and  the amount of sales for each customer.
' 
'  The following sample output shows the summarizing of values 
'  for each unique attribute value:
'  FREQUENCY	TYPE	ZIP	SALES
'	3	Cafe	30308	144438.80
'	3	Cafe	30309	192024.17
'	2	Theater	30308	110825.41
'	1	Theater	30312	30117.69
'	1	Theater	30318	55799.80
'
workspace E:\arcgis\ArcTutor\Geocoding\Atlanta\Atlanta.mdb
Frequency customers customers_freq type;zip SALES

Scripting syntax
About getting started with writing geoprocessing scripts
Frequency_analysis (in_table, out_table, frequency_fields, summary_fields)

Parameter	Explanation	Data Type
in_table (Required)	The table containing the field(s) that will be used to calculate frequency statistics. It can be an INFO or OLE DB table, a dBASE or a VPF table, or a feature class.	Table View \| Raster Layer
out_table (Required)	The table that will store the calculated frequency statistics.	Table
frequency_fields (Required)	The attribute field or fields that will be used to calculate frequency statistics.	Field
summary_fields (Optional)	The attribute field or fields that will be used to summarize the frequency results.	Field

Data types for geoprocessing tool parameters

Script example

# Purpose: Break all multipart features into singlepart features, 
#  and generate a report of which features were separated.

# Create the geoprocessor
import arcgisscripting
gp = arcgisscripting.create()

# Create variables for the input and output feature classes
inFeatureClass = "c:/gdb.mdb/vegetation"
outFeatureClass = "c:/gdb.mdb/vegetation_singlepart"

# Use error trapping in case a problem occurs when running the tool
try:
    # Add a field to the input (if not already present), this will be used as a unique identifier
    if not gp.ListFields(inFeatureClass,"tmpUID").Next():
        gp.AddField(inFeatureClass, "tmpUID","double")

    # Determine what the name of the Object ID is 
    fields = gp.listfields(inFeatureClass, "","oid")  
    OidFieldName = fields.next().name

    # Calculate the tmpUID to the OID since this is a Personal GDB, wrap the Field inside []
    exp = "[" + OidFieldName + "]"
    gp.CalculateField(inFeatureClass, "tmpUID", exp)

    # Run the tool to create a new fc with only singlepart features
    gp.MultipartToSinglepart(inFeatureClass,outFeatureClass)

    # Check if there is a different number of features in the output than there was in the input 
    if (gp.GetCount(inFeatureClass) == (gp.GetCount(outFeatureClass))):
        print "The number of features in the input is the same as in the output, so no multipart features were found"
    else:
        # If there is a difference, print out the FID of the input features which were multipart
        gp.Frequency(outFeatureClass, outFeatureClass + "_freq", "tmpUID")

        # Use a search cursor to go through the table, and print the tmpUID 
        print "Below is a list of the FIDs of all the multipart features from " + inFeatureClass
        rows = gp.SearchCursor(outFeatureClass + "_freq", "[FREQUENCY] > 1")
        row = rows.next()
        while row:
            print int(row.tmpUID)
            row = rows.next()

except:
    # If an error occurred, print out the error message
    print "Error occurred"
    print gp.GetMessages()

Frequency (Analysis) (ArcInfo only)

Command line example

Script example