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BUILT-IN MATHEMATICA SYMBOL

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Evaluate

Evaluate[expr]
causes expr to be evaluated even if it appears as the argument of a function whose attributes specify that it should be held unevaluated.

MORE INFORMATION

You can use Evaluate to override HoldFirst, etc. attributes of built-in functions.

Evaluate only overrides HoldFirst, etc. attributes when it appears directly as the head of the function argument that would otherwise be held. »

EXAMPLES

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Basic Examples (1)

Evaluate inside a Hold:

In[1]:=

Out[1]=

Scope (1)

Evaluate works for arguments of any symbol with attributes HoldAll, HoldFirst, or HoldRest:

Since Attributes is HoldAll, use Evaluate to find the properties of the value of x:

Applications (3)

Unprotect a system symbol to make a definition for it:

Restore protection:

Force evaluation of the right-hand side of a delayed definition:

Build a function from an expression:

Properties & Relations (3)

Evaluate does not work inside functions with attribute HoldAllComplete:

Use Unevaluated to temporarily treat a function as if it were HoldAll:

Evaluate does not work inside Unevaluated:

Possible Issues (1)

Evaluate works only on the first level, directly inside a held function: