Summary Statistics (Analysis)
Summary
Calculates summary statistics for field(s) in a table.
Usage
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The Output Table will consist of fields containing the result of the statistical operation.
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The following statistical operations are available with this tool: Sum, Mean, Maximum, Minimum, Range, Standard Deviation, Count, First, and Last. The Median operation is not available.
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A field will be created for each statistic type using the following naming convention: SUM_<field>, MAX_<field>, MIN_<field>, RANGE_<field>, STD_<field>, FIRST_<field>, LAST_<field>, COUNT_<field> (where <field> is the name of the input field for which the statistic is computed). The field name is truncated to 10 characters when the output table is a dBASE table.
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If a Case field is specified, statistics will be calculated separately for each unique attribute value. The Output Table will contain only one record if no Case field is specified. If one is specified, there will be one record for each Case field value.
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Null values are excluded from all statistical calculations. For example, the AVERAGE of 10, 5 and NULL is 7.5 ((10+5)/2). The COUNT tool returns the number of values included in the statistical calculation, which in this case is 2.
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The Statistics Field(s) parameter Add Field button is used only in ModelBuilder. In ModelBuilder, where the preceding tool has not been run, or its derived data does not exist, the Statistics Field(s) parameter may not be populated with field names. The Add Field button allows you to add expected field(s) so you can complete the Summary Statistics dialog and continue to build your model.
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When using layers, only the currently selected features are used to calculate statistics.
Syntax
| Parameter | Explanation | Data Type |
in_table |
The input table containing the field(s) that will be used to calculate statistics. The input can be an INFO table, a dBASE table, an OLE DB table, a VPF table, or a feature class. | Table View; Raster Layer |
out_table |
The output dBASE or geodatabase table that will store the calculated statistics. | Table |
statistics_fields [[field, statistics_type],...] |
The numeric field containing attribute values used to calculate the specified statistic. Multiple statistic and field combinations may be specified. Null values are excluded from all statistical calculations. The Add Field button, which is used only in ModelBuilder, allows you to add expected field(s) so you can complete the dialog box and continue to build your model. Available statistics types are:
| Value Table |
case_field [case_field,...] (Optional) |
The fields in the Input Table used to calculate statistics separately for each unique attribute value (or combination of attribute values when multiple fields are specified). | Field |
Code Sample
The following Python window script demonstrates how to use the Statistics tool in immediate mode.
import arcpy
from arcpy import env
env.workspace = "C:/data/Habitat_Analysis.gdb"
arcpy.Statistics_analysis("futrds", "C:/output/output.gdb/stats", [["Shape_Length", "SUM"]], "NM")
The following stand-alone script summarizes the vegetation by area within 150 feet of major roads.
# Name: Statistics_Example2.py
# Description: Summarize the vegetation by area within 150 feet of major roads
# Import system modules
import arcpy
from arcpy import env
# Set environment settings
env.workspace = "C:/data"
# Set local variables
inRoads = "majorrds.shp"
outBuffer = "C:/output/output.gdb/buffer_out"
bufferDistance = "250 feet"
inVegetation = "Habitat_Analysis.gdb/vegtype"
outClip = "C:/output/output.gdb/clip_out"
joinField = "HOLLAND95"
joinTable = "c:/data/vegtable.dbf"
joinedField = "HABITAT"
outStatsTable = "C:/output/output.gdb/stats_out"
statsFields = [["Shape_Area", "SUM"]]
# Execute Buffer to get a buffer of major roads
arcpy.Buffer_analysis(inRoads, outBuffer, bufferDistance, dissolve_option = "ALL")
# Execute Clip using the buffer output to get a clipped feature class
# of vegetation
arcpy.Clip_analysis(inVegetation, outBuffer, outClip)
# Execute JoinField to add the vegetation type
arcpy.JoinField_management(outClip, joinField, joinTable, joinField, joinedField)
# Execute Statistics to get the area of each vegetation type within
# the clipped buffer.
arcpy.Statistics_analysis(outClip, outStatsTable, statsFields, joinedField)
The following stand-alone script loops through the attribute fields of a dataset and constructs the Statistics Field(s) parameter so that the SUM statistic is calculated for every numeric field.
# Name: Statistics_Example3_SUM_All.py
# Description: Script that runs the Summary Statistic tool to calculate the
# Sum statistic for every numeric field based on a unique case field
# Import system modules
import arcpy
# Set environment settings
env.workspace = "C:/data/f.gdb"
# Set local variables
intable = "intable"
outtable = "sumstats"
casefield = "Name"
stats = []
# Loop through all fields in the Input Table
for field in arcpy.ListFields(intable):
# Just find the fields that have a numeric type
if field.type in ("Double", "Integer", "Single", "SmallInteger"):
# Add the field name and Sum statistic type
# to the list of fields to summarize
stats.append([field.name, "Sum"])
# Correct formatting of stats [["Field1", "Sum"], ["Field2", "Sum"], ...]
# Run the Summary Statistics tool with the stats list
arcpy.Statistics_analysis(intable, outtable, stats, casefield)