This document provides an overview of Swift basics, including data types, strings, collection types, control flow, and connecting user interface controls to code. It covers topics like integers, floating point numbers, booleans, tuples, arrays, dictionaries, if/else statements, for/forEach loops, while loops, switch statements, and more. The document is presented as a tutorial by Ahmed Ali on iOS development using the Swift programming language.

1. SWIFT BASICS (2)
iOS Development using Swift
Ahmed Ali

2. TODAY TOPICS
• Data types
• Strings
• Mutability, comparison, and interpolation
• Collection types
• Arrays, dictionaries and their mutability
• Control flow
• Connecting UI Controls to Your Code
Ahmed Ali

3. DATA TYPES
• Integers
• Int
• UInt
• Floating point
• Float
• Double
• Boolean
• Bool
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4. DATA TYPES - TUPLES
• Multi-values in one reference
• You can pass a tuple as a method parameter, return it from a function (or method), make
it the type of a reference.
• Definition Syntax:
• var tupleVar : (Int, String)
• Assigning it a value:
• tupleVar = (5, "String value”)
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5. DATA TYPES - TUPLES (CONT)
• Tuples values can be access through their index number or names
• Accessing the value through its zero-based index
let intVal : Int = tupleVar.0 // equal to 5
let strVal : String = tupleVar.1 // equal to "String Value”
• Named tuple elements
let response : (errorCode: Int, errorMessage: String) =
(404, "HTTP not found")
print("Error connecting: (response.errorMessage) with error code:
(response.errorCode)")
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6. STRINGS
• Syntax:
• let myStr = "String value”
• Mutability (modifiable)
• If the reference is defined with var keyword then it is mutable (can be modified)
• If the reference is defined with let keyword then it is immutable (can not be modified)
• Examples:
//Valid
var myStr = "String value"
myStr += " Additional string"
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7. STRINGS (CONT)
• Mutability invalid example:
//Invalid
let myStr = "String value"
myStr += " Additional string"
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8. STRINGS (CONT)
• Comparison:
• You don’t need to call a special method to compare to string references.
• You can use the == operator is used to compare two string reference and see if they
hold the same string value.
• The === can also check against the reference it self, this operator checks if both
reference are the same, i.e refers to the same memory address.
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9. STRINGS (CONT)
• Interpolation
• Simple syntax:
let hello = "Hello”
let world = "World”
let symbol = "!“
let helloWorld = "(hello) (world) (symbol)"
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10. COLLECTION TYPES - ARRAYS
• Can hold list of values of the same type.
• Definition syntax:
let arr : Array<String> = ["val 1", "val 2", "etc..."]
//shorthand version
let arr : [String] = ["val 1", "val 2", "etc..."]
//Shorter version using type inference
let arr = ["val 1", "val 2", "etc..."]
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11. COLLECTION TYPES - ARRAYS (CONT)
• Access and modify array content:
//to be modified, it must be a variable
var arr = ["v1", "v2", "v3"]
println(arr[0]) //prints first element
arr[0] = "newV1" //changes first element
println(arr[0])
arr.removeAtIndex(1) //removes second element
arr.append("anotherNewValue")//appends an element
arr += ["v4", "v5"] //append more than one element
Ahmed Ali

12. COLLECTION TYPES - DICTIONARIES
• Can hold list of key : value pairs.
• Definition syntax:
let dict : Dictionary<String, Int> = ["A" : 15,
"B" : 16]
//shorthand version
let dict : [String: Int] = ["A" : 15, "B" : 16]
//Shorter version using type inference
let dict = ["A" : 15, "B" : 16]
Ahmed Ali

13. COLLECTION TYPES - DICTIONARIES (CONT)
• Access and modify dictionary content:
//to be modified, it must be a variable
var dict : Dictionary<String, Int> = ["A" : 15,
"B" : 16]
println(dict["B"]) //prints 16
dict["B"] = 30 //modifies the value of "B" key
dict["C"] = 19 //adds new key : value pairs to the dictionary
dict.removeValueForKey("A") //removes the key with its value
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14. CONTROL FLOW - IF
• Like any traditional if condition you are familiar with, with additional capabilities.
• Optional binding:
var dict = ["K" : 15, "G" : 16, ”A" : 5]
if let value = dict["A"]{
println(value)
}
Ahmed Ali

15. CONTROL FLOW - IF (CONT)
• If condition binding variable to a tuple
• We can use optional binding to map tuple values to variables
let params = ["name" : "Ahmed", "pass" : "123456"]
if let (cached, response) = performHttpRequest("login", params){
}
//or if only one value matters
if let (_, response) = performHttpRequest("login", params){
}
Ahmed Ali

16. CONTROL FLOW – FOR
• Traditional for loop and varieties of for each
• Traditional for loop:
let arr = [1, 2, 3, 4, 5, 6, 7]
//The parentheses here are mandatory in this old style for loop
for (var i = 0; i < arr.count; i++){
}
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17. CONTROL FLOW – FOR EACH
• For each
• Removing the parentheses is mandatory for all varieties of for each loop
• For each with open range operator:
for i in 0 ... 10 {
//this loop will loop from the value 0 to the value 10 (11 loops)
}
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18. CONTROL FLOW – FOR EACH (CONT)
• For each with half open operator:
for i in 0 ..< 10 {
//this loop will loop from the value 0 to the value 9 (10 loops)
}
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19. CONTROL FLOW – FOR EACH (CONT)
• For each with arrays:
let arr = [1, 2, 3, 4, 5, 6, 7]
for element in arr{
}
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20. CONTROL FLOW – WHILE AND DO .. WHILE
• While and do .. While, has nothing different than what you already from Java, C, C++ or
PHP.
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21. • No implicit fallthrough.
• No need for break statements.
• Use fallthrough if you want the
case to fallthrough.
• Switch cases can be against non-numeric
types.
• Switch cases are exhaustive: all
possible values must have a matching
case.
• Have many varieties to handle range
matches, tuple mapping, where
conditions, and bindings.
let myConst = 2;
switch myConst{
case 1:
println("myConst = 1")
case 2:
println("myConst = 2")
case 3:
println("myConst = 3")
default:
println("myConst = (myConst)")
}
CONTROL FLOW - SWITCH
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22. CONTROL FLOW – SWITCH (CONT)
• Range matching example
• Note: all possible numeric values must
have a matching case, so a default
case is mandatory.
switch myConst{
case 0 ... 4:
println("myConst is between 0 and
4")
case 5 ... 50:
println("myConst is between 5 and
50")
case 51 ..< 60:
println("myConst is between 51 and
59")
default:
println("myConst = (myConst)")
}
Ahmed Ali

23. CONTROL FLOW – SWITCH (CONT)
• Fallthrough example
• If the second case is matched, it’ll
cause all the cases beneath it to be
executed as well.
• switch myConst{
• case 0 ... 4:
• println("myConst is between 0 and 4")
• case 5 ... 50:
• println("myConst is between 5 and 50")
• //if this case matched, it'll pass execution to
the all the cases beneath it
• fallthrough
• case 51 ..< 60:
• println("myConst is between 51 and 59")
• default:
• println("myConst = (myConst)")
• }
Ahmed Ali

24. CONTROL FLOW – SWITCH (CONT)
• let x where ?
• Binding and where conditions
switch myConst{
case let x where x >= 0 && x < 5:
println(x);
case 6..<9:
println("between 6 and 8")
case 9, 10, 11, 12:
println("myConst = (myConst)")
default:
println("myConst = (myConst)")
}
Ahmed Ali

25. Connecting UI Controls to Your
Code