Swift Study Notes

Constant: Let product_constant = "iphone6"

Variable: var product_var = "iPad" // you do not need to declare the variable type. The type of the left-side variable is derived based on the value on the right.

Multiple variables can be defined together: var X1 = 30, X2 = "ABC"

You can specify the variable type precisely: var X1: Int = 27 // specify X1 as the int type

Println (X1) // print a single variable

Println ("X1 = \ (X1), X2 = \ (X2)") // print multiple variables

 

Initialization string

VaR emptystring1 = ""

VaR emptystring2 = string ()

VaR string3 = "ABC"

VaR string4 = string ("ABC ")

Comparison string

If (string3 = string4 ){

}

Connection string

Let str1 = "hello"

Let str2 = "world"

VaR str3 = str1 + str2 // str3 is equal to "Hello World"

Str1 + = str2 // str1 is equal to "Hello World"

String case-sensitive Conversion

Let lowerstr = "ABC"

Let upperstr = lowerstr. uppercasestring // uppercase for lowercase

Let lowerstr2 = upperstr. lowercasestring // lower the upper case

 

Tuples constants and variables

Let product1 = (20, "iphone6", 5888)

Let product_name = "iphone4s"

VaR product2 = (10, "\ (product_name)", 3888)

Println (product1) // (20, iPhone 6, 5888)

Println (product2) // (10, iPhone 4 s, 3888)