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findin

findin(a, b)

Returns the indices of elements in collection a that appear in collection b

Examples

julia> findin([1,2,2],[2,4,5])
2-element Array{Int64,1}:
 2
 3

julia> findin([1,2,3],[2,4,5])
1-element Array{Int64,1}:
 2

julia> foo = [2, 5, 7, 5, 2, -1];
julia> bar = [2, 5, 4];
julia> findin(bar, foo)
1
2

julia> a = [10, 20, 30, 40, 50];
julia> b = [20, 40, 60];
julia> findin(a, b)
2-element Array{Int64,1}:
 2
 4

In this example, the function findin returns the indices of elements in the collection a that appear in the collection b. The elements 20 and 40 are present in both a and b, so their indices [2, 4] are returned.

julia> names = ["Alice", "Bob", "Charlie", "David"];
julia> search_names = ["Charlie", "Frank"];
julia> findin(names, search_names)
1-element Array{Int64,1}:
 3

Here, the function findin is used to find the indices of elements in the names array that appear in the search_names array. Only "Charlie" is present in both arrays, so its index 3 is returned.

Common mistake example:

julia> fruits = ["apple", "banana", "orange"];
julia> findin(fruits, "apple")
ArgumentError: `findin` requires the second argument to be an iterable collection, found String

In this example, the second argument to findin should be an iterable collection, but a single string was provided instead. Make sure to pass a collection as the second argument to avoid this error.

See Also

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