for / while loops

for loops

The for-in loop iterate over ranges of numbers, characters in a string, items in an array or a dictionary.

ranges of numbers

for count in 1...4 {

    println("count = \(count)")

}

//Console output:

count = 1

count = 2

count = 3

count = 4

var sum = 0

for count in 1...4 {

    sum += count

    println("sum = \(sum)")

}

//Console output:

sum = 1

sum = 3

sum = 6

sum = 10

Characters in a string

for myChar in "ABCDE" {

    println("\(myChar)")

}

//Console output:

A

B

C

D

E

Items in an array
http://studyswift.blogspot.tw/2014/06/arrays-dictionaries.html

Items in a dictionary
http://studyswift.blogspot.tw/2014/07/dictionaries.html

C-type for loop

for var count = 1; count < 5; count++ {

    println("count = \(count)")

}

//No ( )

//Console output:

count = 1

count = 2

count = 3

count = 4


while loops

var i = 0

while i++ < 5 {

    println("\(i)")

}

//Console output:

1

2

3

4

5

do-while

do {

    println("\(i--)")

} while i > 0

//Console output:
6
5
4
3
2
1

IBM Swift Sandbox Example