Defining variables
Constant
let constantVar = "Hello, World!"
Implicit
var implicitVar = "Hello, World!"
Explicit
var explicitVar: String = "Hello, World!"
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Loop types
Range
for x in 1...5
Iterate through array
for item in [1, 2, 4, 5]
Iterate through dictionary
for (key, value) in ["one":1, "two":2, ...]
Switch methods
switch ["1", "2", "3", 4, 5, 6, (1, 100)] {
case "1":
print("1")
case "2", "3":
print("2 or 3")
print("No fallthrough")
case 4...5:
print("Interval matching")
case (1...100, 1...100):
print("Tuples work the same.")
default:
print("6")
print("Required in switchs")
print("Must be last")
}
TODO: _, value binding, fallthrough, where
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Function signature anatomy
Argument Label |
(optional) Used when calling the function |
Parameter Name |
Used in the implementation of the function |
Return Type |
(optional) Can be a tuple for multiple return values |
throws |
(optional) Causes errors to propagate up. |
func FunctionName(ArgumentLabel ParameterName: String) throws ->
<ReturnType> {
// Code
}
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Event handling
No language constructs available. |
Error handling
Representing errors
enum ErrorEnum: Error {
case ErrorTypeA
case ErrorTypeB: String
}
Propagating Errors Using Throwing Functions
func canThrowErrors() throws -> String
Handling Errors Using Do-Catch
do {
try results = ThrowTypeB()
} catch ErrorEnum.ErrorTypeB(let errorString) {
// Handle error
}
Converting Errors to Optional Values
let x = try? someThrowingFunction()
Disabling Error Propagation
let x = try! someThrowingFunction()
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