Function Repository Resource:

ReplacePartWith

Replace the part of an expression specified by position via a rule

Contributed by: Eric James Parfitt

ResourceFunction["ReplacePartWith"][expr,rule,pos]

applies a replacement rule to the part of expr at position pos.

Examples

Replace parts 1, 3 and 4 with the rule c→e:

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ReplacePartWith takes lists of positions in the same form as generated by Position:

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ReplacePart replaces parts of an expression. Exactly what the part is replaced with is specified in advance:

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ReplacePartWith replaces parts of an expression, and what is replaced is determined by the applied rule:

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Replacing an empty list of positions does not change the expression:

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$ResourceFunction["ReplacePartWith"][h[a, b], _ -> x, {}]$

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Position {} corresponds to the whole expression:

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$ResourceFunction["ReplacePartWith"][h[a, b], _ -> x, {{}}]$

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