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reduce(op, itr)

reduce(op, itr)

Like reduce(op, v0, itr). This cannot be used with empty collections, except for some special cases (e.g. when op is one of +, *, max, min, &, |) when Julia can determine the neutral element of op.

Examples

julia> reduce(-, 1:5)
-13

julia> reduce(+, 1:5)
15

1. Calculate the sum of an array:

   julia> arr = [1, 2, 3, 4, 5];
   julia> reduce(+, 0, arr)
   15

   This example uses the reduce function to calculate the sum of all elements in the array arr. The + operator is used as the binary operator, and 0 is the neutral element for addition.

2. Find the maximum value in a collection:

   julia> collection = [7, 2, 9, 5, 1];
   julia> reduce(maximum, collection)
   9

   Here, the reduce function is used with the maximum function to find the maximum value in the collection.

3. Concatenate strings in a collection:

   julia> strings = ["Hello", ", ", "world", "!"];
   julia> reduce(*, strings)
   "Hello, world!"

   In this example, the reduce function is used with the * operator to concatenate the strings in the collection.

4. Handle empty collections with a default value:

   julia> empty_collection = Int[];
   julia> reduce(+, 0, empty_collection)
   0

   When reducing an empty collection, the v0 value (in this case, 0) is returned as the result.

Note: It is recommended to use specialized functions like sum, prod, maximum, etc., when applicable, as they have optimized implementations for specific operations.

See Also

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