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swiftsubscript

Swift: Can not access/set an empty array's first item by subscript

Why can not access/set an empty array's first item by subscript？

eg:

var array: [Int] = []
array[0] = 1 //fatal error: Index out of range
Solution

  • By var array: [Int] = [] you create empty array, so it doesn't have values with index 0.

    To fix that you can append to the array like:

    array.append(1)
print(array[0]) // 1

    or set the array of values to your empty array:

    array = [1] // another way to do that: "array += [1]"
print(array[0]) // 1

    or predefine array filled with any values (0 for example):

    let n = 10
array = Array(repeating: 0, count: 10)
array[0] = 0