Wolfram Function Repository
Instant-use add-on functions for the Wolfram Language
Function Repository Resource:
Convert an expression to a pure function by specifying which symbols should be used as input arguments
ResourceFunction["ExpressionToFunction"][expr,var1,var2,…] returns Function[{var1,var2,…},expr]. | |
ResourceFunction["ExpressionToFunction"][expr,…,{vari,1,vari,2,…},…] bundles {vari,1,vari,2,…} together in one function slot as a vector argument. | |
ResourceFunction["ExpressionToFunction"][expr,varspec1→index1,varspec2→index2,…] binds variables specified by varspeci to Slot[indexi]. |
Attributes | None | attributes that the pure function should have |
Evaluated | False | whether to evaluate the function body |
Create a function from a simple polynomial:
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Evaluate the polynomial at a given value:
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Convert a multivariate PDF to a function:
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Bind x and y to the first slot of the function as a vector:
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Bind arguments to keys in an Association:
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Bind multiple symbols to a single slot:
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Combine named slots with positional slots:
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Use the Attributes option to return a function that holds its arguments:
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By default, the function body remains unevaluated:
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Use Evaluated → True to evaluate the PDF:
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When x has a value, using Evaluate directly on the first argument gives the wrong result:
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Use Evaluated → True to Block x while the body is being evaluated:
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Group x and y together as a vector argument and map over a list of points:
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Add a parameter of the PDF as an argument:
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Convert the solution of a differential equation to a function:
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Represent the function at parameter value a=10 with OperatorApplied, then map over a range of x values:
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The resource function ExpressionToFunctionOperator is the operator form of ExpressionToFunction:
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Note, in particular, that both functions hold the expression that's being transformed into a function unless Evaluated→True is used:
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With evaluation of the expression:
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ExpressionToFunction is meant for expressions that do not already contain functions and may malfunction for such expressions if the replacement variables exist inside such functions:
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The correct result would be:
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The problem can sometimes be avoided by evaluating the inner function away:
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Wolfram Language 11.3 (March 2018) or above
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