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Swift for Beginners

What Swift is
Output with print and comments
Compile errors
Quiz — output and errors

Constants and variables
Quiz — assigning to a let
Basic types
Type conversion
Quiz — Int from Double
String interpolation
Quiz — interpolation

Arithmetic
Quiz — division
Overflow
Quiz — overflow
Comparison and logic
Ranges and the ternary operator
Quiz — a range

if and else
Quiz — a number as a condition
switch
Patterns in switch
Quiz — switch

The for-in loop
Quiz — stride
while and repeat-while
break and continue
Quiz — loops

Functions
Argument labels
Quiz — an argument label
Several results
Parameters and inout
Quiz — inout
Recursion
The call stack
Quiz — recursion

A value or nil
Quiz — an optional
if let
guard let
Quiz — guard
?? and ?.
Force unwrapping
Quiz — ?? and !

Strings
Characters and Unicode
Quiz — count
Why s[0] does not work
Quiz — a string index
String methods
Quiz — split and joined

Arrays and indices
Changing an array
Searching an array
Quiz — an array
Looping over an array
Quiz — enumerated
Copies of arrays
Quiz — a copied array

Dictionaries
Looping over a dictionary
Counting with a dictionary
Quiz — a dictionary
Sets
Quiz — a set

Functions as values
Closure syntax
Quiz — a closure
map, filter, reduce
compactMap and optionals
Quiz — chains of calls
Capturing values
Quiz — capturing

Enums
Raw values
Quiz — rawValue
Associated values
Quiz — kinds of values
Enum methods
Optional as an enum
Quiz — switching on an enum

Structs
Methods and mutating
Quiz — mutating
Computed properties and observers
Initializers
Type properties and methods
Quiz — properties
A struct is copied
Quiz — a copied struct

Classes
Quiz — a reference to an object
let and an object reference
Quiz — let with a class and a struct
Inheritance
Quiz — override
Subclass initializers and final
Type checks and casts
Struct or class
Quiz — struct and class

Protocols
Quiz — a protocol
Extensions
Default implementations
Quiz — extensions
Standard protocols
Quiz — standard protocols
Generic functions and types
Quiz — a type constraint

Errors and throw
Quiz — throw
catch and passing an error on
try? and try!
Quiz — try?
defer
Quiz — defer

Reference counting
Quiz — deinit
A strong reference cycle
weak and unowned
Quiz — a reference cycle
Closures and [weak self]
Quiz — [weak self]

Waiting without blocking
async and await
A separate task: Task
Quiz — await
At the same time: async let
Actors
Quiz — an actor

The model: expenses
Totals by category
Parsing input and errors
Quiz — totals
What comes next

Courses/Swift for Beginners

Quiz · Strings and characters · lesson 3 of 7

Quiz — count

What does the program print?

SWIFT

let word = "résumé"
print(word.count, word.utf8.count)

← BackCharacters and Unicode Next →Why s[0] does not work

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