Swift

Using sorted().first or sorted().last can be inefficient, as the entire collection needs to be sorted, which is not required if we only need the minimum or maximum element. This can cause performance issues, especially when dealing with large collections.

Using .first(where:) instead of .filter { }.first in collections, can result in cleaner and more efficient code.

Using .filter {}.last to get the last element of a collection is less efficient than using .last(where:). The former method first iterates through the entire collection to filter the elements and then returns the last element. This is less efficient because it allocates an intermediate buffer/allocation.

Using range(of:) != nil and range(of:) == nil instead of contains can lead to slower performance and less readable code.

Using the filter(where:) method followed by the count property to determine if a collection contains a specific element is not as efficient as using the contains method directly.

Using reduce(_:_:) instead of reduce(into:_:) for copy-on-write types can lead to unnecessary copies of the original collection, resulting in decreased performance and increased memory usage. This is because reduce(_:_:) creates a new copy of the collection on each iteration,

Using the reduce method with a boolean value to check if any or all elements in a sequence satisfy a condition is less performant than using the .allSatisfy() or .contains() method.

Using filter(where:).isEmpty to determine if an array contains an element is a common mistake in Swift. It is an inefficient way of checking if an element exists in an array, as it requires iterating over the entire array

Using the contains method is a more readable and performant way to check if an element exists in an array instead of using first(where:) != nil or firstIndex(where:) != nil.

Using isEmpty to check if a collection is empty is more efficient and concise than comparing the collection to an empty array or dictionary literal. Comparing collections to empty literals can lead to subtle bugs and

Using map followed by reduce to transform and aggregate a collection requires two separate iterations over the collection. This can lead to performance issues when dealing with large collections. Instead, it is recommended to use flatMap to achieve the same result in a single iteration.

Using isEmpty is a more efficient and readable way to check if a collection is empty than comparing its count property to zero. When using count to check if a collection is empty, if the collection does not implement RandomAccessCollection, the runtime must iterate over all elements of the collection to count them before comparing the result to zero.

It's better to check whether a string is empty or not using the isEmpty property rather than comparing it to an empty string literal. Why is this an issue: Comparing a string to an empty string literal is less efficient than using the isEmpty property.