Calculate Value (ModelBuilder)

Summary

Returns a value based on a specified Python expression.

Learn how Calculate Value works in ModelBuilder

Usage

  • This tool is only available from ModelBuilder for use in models. The tool is not available from the Geoprocessing pane or from Python.

  • The Expression parameter only supports Python expressions. Other scripting languages are not supported.

  • Use the Expression parameter for short one line expressions. Use the Code Block parameter for more complicated expressions, such as multiline calculations or logical operations (if, then). The Code Block parameter cannot be used on its own; it must be used in conjunction with the Expression parameter.

    See examples of using the Expression parameter.

  • Variables created in ModelBuilder can be used by this tool, but they cannot be used directly in the Expression parameter. To use a variable in the expression, enclose the variable name in percent signs (%) or double-click the variable name in the Variables list to add it to the Expression parameter.

  • To use a Python function in an expression, double-click a function in the Functions list to add it to the Expression parameter.

    Calculate Value Tool with Variable and Functions list
  • You cannot access model variables in the Code Block parameter. These variables must be passed to the code block from the expression. To do this, create a function definition in the Code Block parameter and reference the definition in the Expression parameter.

    See examples of using the Code Block parameter.

  • The Data Type parameter is used in ModelBuilder to help chain the output of this tool with other tools. For example, if you use this tool to calculate a distance for use as input to the Buffer Distance parameter of the Buffer tool, specify Linear Unit for the Data Type parameter value.

    See examples of using the Data Type parameter.

  • In Python, proper indentation is part of the syntax. The indentation level (two spaces or four spaces) does not matter as long as it is consistent throughout the code block.

  • Note:

    When writing equivalent Python scripts, use standard Python statements instead of using this tool.

Parameters

LabelExplanationData Type
Expression

The Python expression that will be evaluated.

Use the Expression parameter for short one line expressions. Use the Code Block parameter for more complicated expressions, such as multiline calculations or logical operations (if, then). The Code Block parameter cannot be used on its own; it must be used in conjunction with the Expression parameter.

SQL Expression
Code Block
(Optional)

A Python code block. The code in the code block must be referenced in the Expression parameter.

String
Data type
(Optional)

Specifies the data type of the return value of the Python expression. This parameter helps chain Calculate Value with other tools.

  • 3D Object Feature Layer3D Object Feature Layer
  • 3D Tiles Layer3D Tiles Layer
  • Address LocatorAddress Locator
  • Analysis Cell SizeAnalysis Cell Size
  • Annotation LayerAnnotation Layer
  • Any ValueAny Value
  • ArcMap DocumentArcMap Document
  • Areal UnitAreal Unit
  • BIM File WorkspaceBIM File Workspace
  • BooleanBoolean
  • Building Discipline LayerBuilding Discipline Layer
  • Building Scene Discipline LayerBuilding Scene Discipline Layer
  • Building LayerBuilding Layer
  • Building Scene LayerBuilding Scene Layer
  • CAD Drawing DatasetCAD Drawing Dataset
  • Calculator ExpressionCalculator Expression
  • Catalog LayerCatalog Layer
  • Catalog RootCatalog Root
  • Cell SizeCell Size
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  • CompressionCompression
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  • Coverage Feature ClassCoverage Feature Class
  • Data ElementData Element
  • Data FileData File
  • Database ConnectionsDatabase Connections
  • DatasetDataset
  • DateDate
  • dBASE TabledBASE Table
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  • DoubleDouble
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  • GraphGraph
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  • Graphics LayerGraphics Layer
  • Group LayerGroup Layer
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  • IndexIndex
  • INFO ExpressionINFO Expression
  • INFO ItemINFO Item
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  • KML LayerKML Layer
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  • LayerLayer
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  • M DomainM Domain
  • MapMap
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  • NeighborhoodNeighborhood
  • Network Analyst Class FieldMapNetwork Analyst Class FieldMap
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  • Network Analyst LayerNetwork Analyst Layer
  • Network Data SourceNetwork Data Source
  • Network DatasetNetwork Dataset
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  • Network Travel ModeNetwork Travel Mode
  • Oriented Imagery LayerOriented Imagery Layer
  • Parcel FabricParcel Fabric
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  • Parcel LayerParcel Layer
  • PointPoint
  • PolygonPolygon
  • Projection FileProjection File
  • PyramidPyramid
  • RadiusRadius
  • Random Number GeneratorRandom Number Generator
  • Raster BandRaster Band
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  • Raster CatalogRaster Catalog
  • Raster Catalog LayerRaster Catalog Layer
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  • Raster DatasetRaster Dataset
  • Raster LayerRaster Layer
  • Raster StatisticsRaster Statistics
  • Raster TypeRaster Type
  • Record SetRecord Set
  • Relationship ClassRelationship Class
  • RemapRemap
  • ReportReport
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  • Scene LayerScene Layer
  • SemivariogramSemivariogram
  • ServerConnectionServerConnection
  • ShapefileShapefile
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  • SQL ExpressionSQL Expression
  • StringString
  • String HiddenString Hidden
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  • WMS MapWMS Map
  • WMTS LayerWMTS Layer
  • WorkspaceWorkspace
  • XY DomainXY Domain
  • Z DomainZ Domain
String

Derived Output

LabelExplanationData Type
Value

The calculated value.

Data Element; Layer; Table View

Environments

This tool does not use any geoprocessing environments.

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes

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