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What is array.prefix(_:) in Swift?
Theodore Kelechukwu OnyejiakuOverview
The array.prefix(_:) method is used to return a new array that contains the number of elements specified by the argument that is passed to it. This means that if we pass 2 as our argument and call this method, the first two elements will be returned in the new array.
Syntax
arr.prefix(maxLength)
Parameters
arr: This is the array that we want to return a new array from.
maxLength: This is the maximum number of elements that can be returned in the new array. It must be greater than or equal to zero.
Return value
The value returned is a new array, starting at the beginning of the original array arr with a number of elements that is equal to or greater than maxLength.
Code example
// create arrays let numbers = [2, 1, 45, 3, 9] let fruits = ["orange", "apple", "banana", "water-melon", "grape"] let gnaam = ["Google", "Netflix", "Amazon", "Apple", "Meta"] // get some elements // and print results print(numbers.prefix(2)) // [2,1] print(fruits.prefix(0)) // [] print(gnaam.prefix(5)) // ["Google", "Netflix", "Amazon", "Apple", "Meta"]
Get the specified number of elements from an array
Code explanation
- Lines 2–4: We create arrays and initialize them with elements.
- Lines 8–10: We invoke the
prefix(_:)method, along with some arguments. Then, we print the results to the console.
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Theodore Kelechukwu OnyejiakuRELATED COURSES
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