Swift Live Reference

From Coder Merlin
(Redirected from Swift Syntax Live Reference)
Within these castle walls be forged Mavens of Computer Science ...
— Merlin, The Coder


Comments[edit]

Comments are used by humans to document code for other humans. They have no effect on the program itself.

Single-line comments[edit]

CoderMerlin™ Code Explorer: W0000 (1)


Multi-line comments[edit]

CoderMerlin™ Code Explorer: W0000 (2)


Output[edit]

print[edit]

CoderMerlin™ Code Explorer: W0000 (3)


print with separator[edit]

CoderMerlin™ Code Explorer: W0000 (4)


print with terminator[edit]

CoderMerlin™ Code Explorer: W0000 (5)


Types[edit]

In Swift, it is customary to capitalize all types.

Int
A signed integer value type
Float
A single-precision, floating-point value type
Double
A double-precision, floating-point value type
String
A Unicode string value that is a collection of characters

Constant and Variable Declarations[edit]

Constant Declarations[edit]

Constants (named values which should never change) use the let keyword


CoderMerlin™ Code Explorer: W0000 (6)


Variable Declarations[edit]

Variables (named values which may change) use the var keyword


CoderMerlin™ Code Explorer: W0000 (7)


Control Structures[edit]

Control structures are used to alter the otherwise sequential flow of a program.

Conditionals[edit]

Conditionals are used to execute a segment of code based upon a condition being met.

if[edit]

CoderMerlin™ Code Explorer: W0000 (9)


else[edit]

if n < 10 {
    print("n is less than 10")
} else {
    print("n is not less than 10")
}

switch[edit]

switch n {
    case 0:
        print("n is zero")
    case 1:
        print("n is one")
    default:
        print("n is neither one nor zero")
}

Loops[edit]

Loops are used to repeat a segment of code until a condition is met.

for[edit]

for loops are helpful when the number of iterations is known.

// From zero up to but excluding ten
for n in 0 ..< 10 {
    print(n)
}

// From one up to and including ten
for n in 1 ... 10 {
    print(n)
}

while[edit]

while loops are helpful when the condition may initially be false and the statements should not be executed.

while n < 10 {
    n += 1
}

repeat while[edit]

repeat while loops are helpful when the statements should be executed at least once.

repeat {
    n += 1
} while n < 10

References[edit]