Swift Array capacity

The capacity property returns the number of elements of the array without allocating any additional storage.


var languages = ["Swift", "C", "Java"]

// check if leanguages is empty or not var result = languages.capacity
print(result) // Output: 3

capacity Syntax

The syntax of the array capacity property is:


Here, array is an object of the Array class.

capacity Return Values

The capacity property returns the total number of elements present in the array without allocating any additional storage.

Example 1: Swift Array capacity

var names = ["Gregory", "Perry", "Nadal"]

// capacity total elements on names print(names.capacity)
var employees = [String]()
// capacity total elements on employees print(employees.capacity)



In the above example, since

  • names contain three string elements, the property returns 3.
  • employees is an empty array, the property returns 0.

The capacity property here returns a total number of elements without allocating new storage.

Example 2: Using capacity With if...else

var numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

// false because there are 10 elements on numbers if (numbers.capacity < 5) {
print("The array size is small") } else { print("The array size is large") }


The array size is large

In the above example, we have created the array named numbers with 10 elements.

Here, since there are 10 elements in the array, numbers.capacity < 5 evaluates to false, so the statement inside the else block is executed.

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