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Instant-use add-on functions for the Wolfram Language
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Map a function at parts of an expression that match a given pattern
ResourceFunction["MapCases"][f,{e1,e2,…},pattern] applies f to each ei that matches pattern. | |
ResourceFunction["MapCases"][f,expr,pattern,levelspec] applies at levels specified by levelspec. | |
ResourceFunction["MapCases"][f,pattern] represents an operator form of ResourceFunction["MapCases"] that can be applied to an expression. |
Map a function at integers only:
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Map a function at anything other than integers:
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Use the operator form of MapCases:
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Map at matching elements in an Association:
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Apply a function to strings only:
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Apply a function to cases of lists of integers:
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Apply a function to nonzero values only:
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Apply a function to cases of lists of integers at any level:
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Map at symbols among the elements of an expression:
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Also include the head of the expression in the search:
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By default, the f[ei] will remain unevaluated if the ei is found within a held expression:
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Evaluate each of the f[ei] when applying:
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Convert all symbols in an expression to strings:
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Include heads:
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MapCases[f,expr,_] is equivalent to Map[f,expr]:
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MapCases[f,expr,pattern,levelspec] is equivalent to Replace[expr,e:pattern⧴f[e],levelspec]:
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MapCases[f,expr,pattern,levelspec] is equivalent to MapAt[f,expr,Position[expr,pattern,levelspec]]:
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When using the option "EvaluateCases"→True, these equivalencies no longer necessarily hold:
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MapCases by default starts at level 1, so it does not apply the function to the whole expression:
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In MapCases[f,expr,pattern], the pattern will evaluate before matching unless wrapped in HoldPattern:
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Highlight integers in an expression:
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Wolfram Language 11.3 (March 2018) or above
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