Summary of "IOS" swift data types, operators, new statements, etc.

Summarize and review some of the basic things, mainly with OC different and new.

I. Basic data types

Int, Float, Double, Bool, Character, String (uppercase in first letter)
Array, Dictionary, tuple type (tuple), optional type (Optional)

Specify the data type:

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1. Let A:int = Ten //Specifies the data type. Generally do not need to specify, will automatically determine the type. (initialization required when used)

1.1 Shaping

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1. 1.1 Shaping
2. Let maxInt = Int.max //Get maximum value of type Int
3. Let minint = Int.min
5. Let A1 = Ten //Decimal
6. Let A2 = 0b1010 //binary starts with 0b
7. Let a3 = 0o12 //Eight binary starting with 0o
8. Let A4 = 0xA //16 binary 0x

1.2 Floating point

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1. 1.2 Floating-point float,double
2. Let B1 = 0.123 //default is double
3. Let B2 = 0.123e3 //123.0

1.3 Bool, keep up with the mainstream ....

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1. 1.3Bool (not yes/no)
2. Let C1 = true
3. Let C2 = false

1.4 Yuan zu

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2. 1.4 tuples. can be n any type of data
4. Let Tup1 = (age:1,name:"abc", hight:2,jj:0.1) //With element name
6. Let tup2 = (1,"abc", 2,0.1) //Omit element name
10. var tup3: (int,string) = (1,"haha") //Specifies the type. (the element name cannot be written again after the type is specified)
14. var (t1,t2) = Tup3 //directly get 2 variables to receive the meta-ancestor
16. var (_,t3) = Tup3 //Receive only one

II. output format of data && type conversion && type Alias

Simplifies a lot.

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1. 2.1 Additional 0 Or _ can be added to the number to enhance read/write
2. Let D1 = 000123
3. Let D2 = 00123.0012300
5. Let D3 = 1_2_3
6. Let D4 = _123//Error

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1. 2.2 Type Conversions
2. Let e1 = 1
3. Let e2 = 0.12
4. Let E3 = e1 + E2//error, different types cannot be added directly
5. Let E3 = Double (E1) + E2 //type conversion

The type alias is equivalent to a typedef in C

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1. 2.3 Type alias Typealias
2. Typealias Xnint = Int
3. Let Test:xnint = 10

Third, the new addition of several operators

3.1 range operator, used on WWDC

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1. 3.1 Range Operator: < ...
2. For index1 in 1...10{} //means closure [1]
3. For index2 in 1..<10{} //= semi-closed [1]

3.2 Overflow operator. (newly added, available to handle data overflow scenarios)

&+ overflow plus &-overflow minus &* overflow multiply &/overflow except &% overflow remainder

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1. Let F1 = Uint.max
2. Let F2 = x + 1//This will overflow the writing
3. Let F2 = f1 &+ 1 //overflow plus. The value is 0. The minimum value after becoming overflow
5. Let G1 = 10
6. Let G2 = g1/0//Will error
7. Let g2 = G1 &/0 //value is 0
8. Let g3 = G1% 0//Will error
9. Let g3 = G1 &% 0 //value is 0

3.3 Some places of attention

Not 0 is really this C language thing is eliminated! The assignment is more flexible, and the assignment has no return value.

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1. Let (x, y) = ( min)//Overall assignment
2. if (x = y) {}//It is wrong to write this. can prevent = = Write =
3. if (10) {}//It is also wrong to write. Non-0 is really no longer applicable.
4. if (true) {}

Iv. Process Control Statements

Adds a new for in statement while the switch statement is more flexible.

4.1 Loop for in

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1. For H1 in 1...10{
2. println (H1)
3. }
5. For _ in 1..<10{ //Do not need to use the value in the range, directly ignore the _
6. println ("# # #")
7. }

4.2 tags (can be used to jump out of the specified loop, to understand)

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2. Xn
4. For _ in 1 ... 3 {
6. println ("* * *")
8. For tmp in 1 ... 5{
10. println ("# # #")
12. //Specify Exit
14. if tmp = = 3{
16. Break xn
18. }
20. }
22. }

4.3 switch statement

1) differs from the C language. Do not write break for each case, auto break
2) There must be an executable statement behind each case, or an error will be
3) Each case can match multiple conditions, or you can fill in a range
4) switch to ensure that all cases are handled, with default.
5) Case can also match meta-ancestor

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2. Let score = Ten
4. Switch score{
6. Case 0 ... 3:
8. println ("poor")
10. Case 4,5,6,7:
12. println ("Liang")
14. Case 8 ... Ten:
16. println ("excellent")
18. Default
20. println ("Super God")

IOS Swift data types, operators, new statements, and more