Swift Dictionary sorted()

let age = ["Ranjit": 1930, "Sabby": 2008 ]

// sort dictionary by key in ascending order
let sortAge = age.sorted(by: <)

print(sortAge)

// Output: [(key: "Ranjit", value: 1930), (key: "Sabby", value: 2008)]

sorted() Syntax

The syntax of the dictionary sorted() method is:

dictionary.sorted(by: {operator})

Here, dictionary is an object of the dictionary class.

sorted() Parameters

The sorted() method can take one parameter:

• operator (optional) - a closure that accepts a condition and returns a Bool value.

Note: If we pass greater-than operator >, the dictionary is sorted in descending order

sorted() Return Value

The sorted() method returns an array of tuples.

Example 1: Swift dictionary sorted()

var info = ["Carlos": 1999, "Nelson": 1987]

// sort dictionary by key in ascending order
let sortInfo = info.sorted(by: > )

print(sortInfo)

Output

[(key: "Nelson", value: 1987), (key: "Carlos", value: 1999)]

Here, we can see that the info dictionary is sorted by key in ascending order of the string. For example, "Carlos" comes before "Nelson" because "C" comes before "N".

Example 2: Sort by Passing Closure

ley info = ["Carlos": 1999, "Nelson": 1987]

// sort dictionary by value in ascending order
let sortInfo = info.sorted(by: { $0.value < $1.value } )

print(sortInfo)

Output

[(key: "Nelson", value: 1987), (key: "Carlos", value: 1999)]

In the above example, we have passed the closure to sort info by value in ascending order. Notice the closure definition,

{ $0.value < $1.value }

This is a short-hand closure that checks whether the first value of info is less than the second value or not.

$0 and $1 is the shortcut to mean the first and second parameters passed into the closure.