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findlast(::Function, A)

findlast(predicate, A)

Return the index of the last element of A for which predicate returns true.

Examples

In the Julia programming language, the function findlast(A, v)

Return the index of the last element equal to v in array A.

julia> A = [1, 2, 3, 2, 4];
julia> findlast(A, 2)
4

Provide common examples of its use. If there are any common mistakes users make, add an example.

1. Find the last occurrence of an element in an array:

   julia> arr = [10, 20, 30, 20, 40];
   julia> findlast(arr, 20)
   4

   This example finds the index of the last occurrence of the element 20 in the array arr.

2. Search for the last occurrence of a value in a vector:

   julia> vector = [1.5, 2.0, 3.5, 2.0, 4.0];
   julia> findlast(vector, 2.0)
   4

   It returns the index of the last occurrence of the value 2.0 in the vector.

3. Handle cases when the element is not found:

   julia> numbers = [1, 2, 3, 4, 5];
   julia> findlast(numbers, 10)
   0

   If the element is not found in the array, it returns 0.

Common mistake example:

julia> arr = [5, 10, 15, 20];
julia> findlast(arr, 30)
ERROR: MethodError: no method matching findlast(::Array{Int64,1}, ::Int64)

In this example, the element 30 is not present in the array. It's important to note that findlast returns 0 when the element is not found, not an error. Check if the element is present in the array before using findlast.

See Also

User Contributed Notes

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