Array
Set
Dictionary
Let's understand one by one :
1. Array
- Most common and Widely used data type.
- Ordered collection of similar types of data.
Declaration:
var normalArray = [Int]() // declaring an empty Int array like this
- The array can be any type in swift.
- We can also declare with some initial values.
- Swift is a strongly typed language so we don’t have to tell the type when we declare an array but we can also specify the type
var normalArray = [2,3,4,5]
var normalArray: [Int] = [2,3,4,5]You also can declare an array with some repeated values or using one or more arrays
var normalArray = Array(repeating: 1, count: 3) //initialize normalArray with three ones var normalArray = arrayOne + arrayTwo //initialize normalArray with addign arrayOne & arrayTwo
- Insert elements into an Array: We can insert an element at the end of the array or in a valid position.
normalArray.append(12) //append element at the end of array
normalArray += [100.0] //append at the endnormalArray.insert(12, at: 0) //insert element at 0 position. This position value should be n to n-1 if array have n number of elements.
- Access Elements of Array: We can access the element of an array using a subscript syntax, passing the index value into it. Also swift provided a list of methods to get values and check different parameters.
normalArray[2] //return second element from array
normalArray.count // return the number of elements in array
normalArray.isEmpty // return false if array is empty
normalArray.capacity // return the number of elements in arraynormalArray.first //get the first element from array
normalArray.last //get the last elements from array
normalArray.max() //get the max element from array
normalArray.min() //get the min element from arraynormalArray.sorted() // sort the array
normalArray.reversed() //reverse an array
normalArray.shuffled() //shuffle the elements of an array
- Replace elements of Array: Array value can set or replace in a specific index or for a range of the index.
normalArray[2] = 1 // replace the value in second index of arraynormalArray[1...3] = [12, 23, 34] // set first to third position value as 12, 23 &34
- Remove elements from Array: Array elements can remove from different ways & different positions.
normalArray.removeAll() // remove allelement from array
normalArray.removeFirst() // remove first element from array
normalArray.removeLast() // remove last element from arraynormalArray.remove(at: 2) //remove second element from arraynormalArray.removeLast(1) // remove the second element from the end index of arraynormalArray.removeFirst(2) // remove the thirdelement from the start index of the array
- Iterate over the array: Every element of an array can be traverse using loop
for i in 0..<normalArray.count{
print(normalArray[i])
}or
for item in normalArray{
print(item)
}
2. Dictionary
- Can hold multiple unordered data in key-value pairs.
- Each value is associated with a unique key and any value from the dictionary can access with the associated key with it.
- Declaration:
var normalDictionary = [Int: String]()
// an empty "normalDictionary" with Int type key & String type value
- The key-value pair of a dictionary can be any type in swift.
- We can also declare with some initial values.
- Swift is a strongly typed language so we don’t have to tell the type of key-value pair when we declare a dictionary but we can also specify the type
var normalDictionary = [1: "John", 2: "Doe"]
var normalDictionary : [Int: String] = [1: "John", 2: "Doe"]- Insert elements into a Dictionary: We can insert a value into the dictionary using a key. If the key already exists it will replace the previous value for this key elsewhere it will add a new value.
normalDictionary[3] = "Mihalos" // Add a value "Mihalos" for key "3"- Access Elements of Dictionary: We can access the elements of a dictionary by using the key. Also swift provided a list of methods to get values and check different parameters.
normalDictionary[2] //return the value of second key-value pair in dictionary normalDictionary.count // return the number of elements in dictionarynormalDictionary.isEmpty // return false if dictionary is emptynormalDictionary.capacity // return the number of elements in dictionarynormalDictionary.first //get the first element from dictionarynormalDictionary.max { a, b in a.value < b.value} // return key-value pair for maximum valuenormalDictionary.min() { a, b in a.value < b.value} // return key-value pair for minimumvaluenormalDictionary.sorted( by: { $0.0 < $1.0 }) // reurn an sorted array of dictionarynormalDictionary.reversed() //return key-value pair in reverse ordernormalDictionary.shuffled() //shuffle the key-value pair of dictionary
- Replace elements from a Dictionary: A value for a key is simply replaced by putting a new value for that key. We also can use “updateValue” method to replace the value for any key. But Remember “updateValue” method returns the previous value as output.
normalDictionary[3] = "Mike"
normalDictionary.updateValue("Duke", forKey: 3)
- Remove elements from Dictionary: Dictionary elements can be removed in a different way.
normalDictionary[3] = nil // remove key-value pair for key "3"
normalDictionary.removeAll() // remove all element from dictionary arraysimpleDictionary.removeAll(keepingCapacity: true) remove all elements with keeping the capacity or not- Iterate over the Dictionary: Every key-value pairs of a dictionary can be traverse using loop
for (key, value) in normalDictionary {
print(key, value)
}Instead of key-value pair we also can access only key or value from dictionary like this
for key in normalDictionary.keys{
print(key)
}for value in normalDictionary.values{
print(value)
}
We also can get the keys and values of a dictionary as an array.
let keys = [Int](normalDictionary.keys) // return all the keys as an array
let values = [String](normalDictionary.values) //return all the values as an array3. Set
- Set is an unordered collection of the same type of data.
- The main characteristic of the set is, set can not have any duplicate elements.
- Declaration: You can declare an empty Int type set like this
var normalSet = Set<Int>() // an empty Int type set- The set can be any type in swift.
- We can also declare with some initial values.
- Swift is a strongly typed language so we don’t have to tell the type when we declare a set but we can also specify the type
var normalSet = Set([10, 20, 30, 40, 20])
varnormalSet: Set<String> = ["John", "Doe", "Hi", "John"]You also can declare a set with some repeated values but you will get a single value for those repeated value cause set didn’t store any duplicate element.
var normalSet = Set(repeatElement(1, count: 3)) // Initialize set with three ones but set will have only one into it.
- Insert elements into a set: We can insert an element at the end of the array or in a valid position.
normalSet.insert(12) // //append element at the end of set- Access Elements of a set: Like array you cannot access set elements using subscript syntax but you can check an element is in the set or not. Also swift provided a list of methods to get values and check different parameters.
normalSet.contains(2) // check an element is in the set or not
normalSet.count // return the number of elements in set
normalSet.isEmpty // return false if set is empty normalSet.capacity // return the number of elements in setnormalSet.first //get the first element from set
normalSet.max() //get the max element from set
normalSet.min() //get the min element from setnormalSet.sorted() // sort the set
normalSet.reversed() // reverse set
normalSet.shuffled() // shuffle set elements
- Remove elements: Set elements can remove from different way & from different positions also.
normalSet.removeFirst() // remove first element from set
normalSet.remove(1) // remove from a specific indexnormalSet.removeAll() // remove all elements from set
normalSet.removeAll(keepingCapacity: true) // remove all elements with keeping the capacity or not
- Iterate over the set: Every element of a set can be traverse using loop
for data in normalSet {
print(data)
}The set type didn’t have any order so if you want to traverse in any order you can do it by swift provided methods
for data in normalSet.sorted() {
print(data)
}for data in normalSet.reversed() {
print(data)
}
- Different set operations: You also can perform different set operations within two sets and each of those operations will create a new set.
normalSet2.union(normalSet3).sorted() // perform union opertion within normalSet2 & normalSet3
normalSet2.intersection(normalSet3) // perform intersection within two set
normalSet2.subtracting(normalSet3) // perform subtracting
normalSet2.symmetricDifference(normalSet3) // perform symmetricDifferencenormalSet2.isSubset(of: normalSet3) // check one set is subset of snother or not
normalSet2.isSuperset(of: normalSet3) // check superset or not
normalSet2.isDisjoint(with: normalSet3) // check disjoint or not
