ValueTable (arcpy)

Summary

A value table is a flexible object that can be used as input for a multivalue parameter. It exists only during the lifetime of the geoprocessing object that created it.

Discussion

setRow's value argument is space delimited. Any value used in the value argument that contains spaces must be enclosed in quotations. In the following example, a value table with two columns has a feature class and an index value added:

value_table.setRow(0, "'c:/temp/land use.shp' 2")

Syntax

ValueTable ({columns})

Parameter	Explanation	Data Type
columns	The number of columns. (The default value is 1)	Integer

Properties

Property	Explanation	Data Type
columnCount (Read Only)	The number of columns.	Integer
rowCount (Read Only)	The number of rows.	Integer

Method Overview

Method	Explanation
addRow (value)	Adds a row to the value table. addRow's value argument is space-delimited. Any value used in the value argument that contains spaces must be enclosed in quotations. In the following example, a value table with two columns has a feature class and an index value added: vtab.addRow("'c:/temp/land use.shp' 2")
exportToString ()	Exports the object to its string representation.
getRow (row)	Gets a row from the value table.
getTrueValue (row, column)	Gets value from a given column and row.
getValue (row, column)	Gets value from a given column and row.
loadFromString (string)	Restore the object using its string representation. The exportToString method can be used to create a string representation.
removeRow (row)	Deletes a row from the value table.
setColumns (number_of_columns)	Sets the number of columns for the value table.
setRow (row, value)	Updates a given row within the value table. setRow's value argument is space-delimited. Any value used in the value argument that contains spaces must be enclosed in quotations. In the following example, a value table with two columns has a feature class and an index value added: vtab.setRow(0, "'c:/temp/land use.shp' 2")
setValue (row, column, value)	Updates the value of a given row and column.

Methods

addRow (value)

Parameter	Explanation	Data Type
value	The row to be added.	Object

exportToString ()

Return Value

Data Type	Explanation
String	The string representation of the object.

getRow (row)

Parameter	Explanation	Data Type
row	The row index position.	Integer

Return Value

Data Type	Explanation
String	A row from the value table.

getTrueValue (row, column)

Parameter	Explanation	Data Type
row	The row index position.	Integer
column	The column index position.	Integer

Return Value

Data Type	Explanation
String	The value of a given column and row.

getValue (row, column)

Parameter	Explanation	Data Type
row	The row index position.	Integer
column	The column index position.	Integer

Return Value

Data Type	Explanation
String	The value of a given column and row.

loadFromString (string)

Parameter	Explanation	Data Type
string	The string representation of the object.	String

removeRow (row)

Parameter	Explanation	Data Type
row	The index position of the row to remove.	Integer

setColumns (number_of_columns)

Parameter	Explanation	Data Type
number_of_columns	The number of columns for the value table.	Integer

setRow (row, value)

Parameter	Explanation	Data Type
row	The index position of the row to update.	Integer
value	The value to update the given row.	Object

setValue (row, column, value)

Parameter	Explanation	Data Type
row	The row index.	Integer
column	The column index	Integer
value	The value to update the given row and column.	Object

Code Sample

ValueTable example

Use ValueTable to hold feature class names and ranks for the Union tool.

import arcpy

# Set the workspace. List all of the feature classes in the dataset
arcpy.env.workspace = "c:/data/landbase.gdb/Wetlands"
feature_classes = arcpy.ListFeatureClasses()

# Create the value table for the Analysis Union tool with 2 columns
value_table = arcpy.ValueTable(2)

# Iterate through the list of feature classes
for fc in feature_classes:
    # Update the value table with a rank of 2 for each record, except
    #   for BigBog
    if fc.lower() != "bigbog":
        value_table.addRow(fc + " 2")
    else:
        value_table.addRow(fc + " 1")

# Union the wetlands feature classes with the land use feature class to create
#   a single feature class with all of the wetlands and land use data
value_table.addRow("c:/data/landbase.gdb/land_use 2")
arcpy.Union_analysis(value_table, "c:/data/landbase.gdb/wetlands_use")

ValueTable example 2

A value table can be populated with a multivalue string that has been passed to a script as an argument, making it easy to extract each record. The example below shows how to do this:

import os
import arcpy

# Set the output workspace
arcpy.env.workspace = arcpy.GetParameterAsText(1)

# Create a value table with 2 columns
value_table = arcpy.ValueTable(2)

# Set the values of the table with the contents of the first argument
value_table.loadFromString(arcpy.GetParameterAsText(0))

# Loop through the list of inputs
for i in xrange(0, value_table.rowCount):
    # Validate the output name for the new workspace
    name = value_table.getRow(i)
    out_name = arcpy.ValidateTableName(os.path.basename(name))

    # Copy the features to the new workspace
    arcpy.CopyFeatures_management(name, out_name)