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[Merged by Bors] - chore(FinEnum): List.nthLe -> List.get #12220

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[Merged by Bors] - chore(FinEnum): List.nthLe -> List.get #12220

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9 changes: 4 additions & 5 deletions Mathlib/Data/FinEnum.lean
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Original file line number Diff line number Diff line change
Expand Up @@ -48,13 +48,12 @@ def ofEquiv (α) {β} [FinEnum α] (h : β ≃ α) : FinEnum β
#align fin_enum.of_equiv FinEnum.ofEquiv

/-- create a `FinEnum` instance from an exhaustive list without duplicates -/
def ofNodupList [DecidableEq α] (xs : List α) (h : ∀ x : α, x ∈ xs) (h' : List.Nodup xs) : FinEnum α
where
def ofNodupList [DecidableEq α] (xs : List α) (h : ∀ x : α, x ∈ xs) (h' : List.Nodup xs) :
FinEnum α where
card := xs.length
equiv :=
⟨fun x => ⟨xs.indexOf x, by rw [List.indexOf_lt_length]; apply h⟩, fun ⟨i, h⟩ =>
xs.nthLe _ h, fun x => by simp, fun ⟨i, h⟩ => by
simp [*]⟩
⟨fun x => ⟨xs.indexOf x, by rw [List.indexOf_lt_length]; apply h⟩, xs.get, fun x => by simp,
fun i => by ext; simp [List.get_indexOf h']⟩
#align fin_enum.of_nodup_list FinEnum.ofNodupList

/-- create a `FinEnum` instance from an exhaustive list; duplicates are removed -/
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