Attack on Swift-------variable, constant

Source file extension for 1.Swift. Swift

2. Two not required: ① do not need to write the main function ② no need to add a semicolon after each statement

3. Multi-line annotations can be nested

4.let declaring a constant VAR declaration variable

Let radius = 10

var x= 0,y = 0,z = 0

5.UIImageView

var ImageView = Uiimageview ()

Imageview.image = UIImage (name: "002.png")

Imageview.frame = CGRectMake (20,20,100,50)

Self.view.addSubview (ImageView)

6.Playground

7. String

①: General form

Let Web = "xxxxxxx"

②: Stitching plus +

Let str = "123"

Let str2 = "456"

Let dest = str + str2

③: Interpolation

Let hand = 2

var age = 20

Let str = "I am (age) year old, have \ (hand) only Hand"

④: Type Conversion

var age = 10

Convert to string: <1>var str = string (age) <2>var str2 = "\ (age)"

8: Print Output function

PRINTLN: Output will be wrapped automatically

Print: Less line wrapping

code example: ①println ("Learn Swift") ②let name = "Learn Swift + learn x\n"; Print (name)

9: Names of constants and variables

Any..... (Control + COMMAND + space-----Pop-up emoji keyboard)

Attention:

Attack on Swift-------variable, constant