Visitar URL original
Initialization—Wolfram Documentation

WOLFRAM

Wolfram Language & System Documentation Center

Initialization

is an option for notebooks, cells, Dynamic, DynamicModule, Manipulate and related constructs that specifies an expression to be evaluated when the construct is first displayed.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Properties & Relations  
Possible Issues  
See Also
Related Guides
Related Workflows
History
Cite this Page

Initialization

Initialization

is an option for notebooks, cells, Dynamic, DynamicModule, Manipulate and related constructs that specifies an expression to be evaluated when the construct is first displayed.

Details

  • The typical usage is Initialization:>expr.
  • Initialization expressions defined in particular cells in a notebook are evaluated when those cells are first made visible, and not necessarily when the notebook is first opened.
  • Initialization expressions are guaranteed to be evaluated exactly once before the contents of the main construct are resolved.
  • An object that is already initialized can be initialized again if it is deleted, then restored as a result of using Undo. If an object is copied and pasted, each pasted copy will initialize again.
  • Initialization expressions may be applied directly to notebooks and cells. Unlike most other option values, the Initialization option of a cell will not inherit any settings applied at the notebook level.

Examples

open all close all

Basic Examples  (4)

Specify an expression to be evaluated before displaying Dynamic:

Wolfram Language code: Dynamic[c[1], Initialization :> (c[x_] := {x})]

DynamicModule:

Wolfram Language code: DynamicModule[{c}, Dynamic[c[1]], Initialization :> (c[x_] := {x})]

Manipulate:

Wolfram Language code: Manipulate[c[n], {n, 0, 1}, Initialization :> (c[x_] := {x})]

For a notebook:

Wolfram Language code: CreateDocument[ExpressionCell[Dynamic[c[1]]], Initialization :> (c[x_] := {x})]

Properties & Relations  (3)

Initialization is guaranteed to only happen once:

Wolfram Language code: DynamicModule[{x = 0}, Table[DynamicModule[{y}, Dynamic[{y, x}], Initialization :> (y = x++)], 10]]

Initialization for outer constructs occurs before initialization for inner constructs:

Wolfram Language code: DynamicModule[{x}, Dynamic[x, Initialization :> (x = "inner")], Initialization :> (x = "outer")]

Each time a Dynamic destroys and recreates an initializing construct, the initialization will run again:

Wolfram Language code: DynamicModule[{inner}, Dynamic[{Row[{"outer: ", RandomColor[]}], Dynamic[Row[{"inner: ", inner}], Initialization :> (inner = RandomColor[])]}, UpdateInterval -> 1]]

Possible Issues  (3)

Loading a package in the initialization does not allow you to use unqualified symbols from that package:

Wolfram Language code: DynamicModule[{x}, Dynamic[x], Initialization :> (Needs["PrimalityProving`"];x = ProvablePrimeQ[1093])]

Doing this properly requires loading the package in the Input cell and loading it in an outer initialization:

Wolfram Language code: Needs["PrimalityProving`"]; DynamicModule[{}, DynamicModule[{x}, Dynamic[x], Initialization :> (x = ProvablePrimeQ[1093])], Initialization :> (Needs["PrimalityProving`"])]

This function produces a cell indicating the current Initialization setting upon that cell:

Wolfram Language code: showInitialization[style_] := ExpressionCell[Row[{TextCell["The cell's Initialization setting is: "], Dynamic[CurrentValue[EvaluationCell[], Initialization]]}], style];

Unlike most options, cells do not inherit Initialization from the notebook setting:

Wolfram Language code: CreateDocument[{showInitialization["Section"]}, Initialization :> "fish"]

Cells still inherit Initialization from named cell styles:

Wolfram Language code: CreateDocument[{showInitialization["FishStyle"]}, StyleDefinitions :> Notebook[{Cell[StyleData["FishStyle"], Initialization :> "fish"]}]]
Wolfram Research (2007), Initialization, Wolfram Language function, https://reference.wolfram.com/language/ref/Initialization.html (updated 2020).

Text

Wolfram Research (2007), Initialization, Wolfram Language function, https://reference.wolfram.com/language/ref/Initialization.html (updated 2020).

CMS

Wolfram Language. 2007. "Initialization." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2020. https://reference.wolfram.com/language/ref/Initialization.html.

APA

Wolfram Language. (2007). Initialization. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Initialization.html

BibTeX

@misc{reference.wolfram_2026_initialization, author="Wolfram Research", title="{Initialization}", year="2020", howpublished="\url{https://reference.wolfram.com/language/ref/Initialization.html}", note=[Accessed: 14-November-2026]}

BibLaTeX

@online{reference.wolfram_2026_initialization, organization={Wolfram Research}, title={Initialization}, year={2020}, url={https://reference.wolfram.com/language/ref/Initialization.html}, note=[Accessed: 14-November-2026]}