9.25. Swift character

The character of Swift is a single character string literal, and the data type is Character .

The following example lists two character instances:

import Cocoa let char1: Character = "A" let char2: Character = "B" print("The value of char1 is \(char1)") print("The value of char2 is \(char2)") 

The output of the above program execution is as follows:

The value of char1 is A The value of char2 is B 

If you want to Character if more characters are stored in the constant of type (character), the program execution will report an error, as shown below:

import Cocoa // The following assignments in Swift will result in an error message let char: Character = "AB" print("Value of char \(char)") 

The output of the above program execution is as follows:

error: cannot convert value of type 'String' to specified type 'Character' let char: Character = "AB" 

9.25.1. Null character variable #

Cannot create empty in Swift Character type variable or constant:

import Cocoa // The following assignments in Swift will result in an error message let char1: Character = "" var char2: Character = "" print("The value of char1 \(char1)") print("The value of char2 \(char2)") 

The output of the above program execution is as follows:

 error: cannot convert value of type 'String' to specified type 'Character' let char1: Character = "" ^~ error: cannot convert value of type 'String' to specified type 'Character' var char2: Character = "" 

9.25.2. Traverse characters in a string #

Swift’s String type represents a specific sequence Character a collection of type values. Each character value represents a Unicode characters.

In Swift 3 String need to pass through characters the property method to be called, which is available in Swift 4 through the String the object itself is called directly, for example:

In Swift 3:

import Cocoa for ch in "Runoob".characters { print(ch) } 

In Swift 4:

import Cocoa for ch in "Runoob" { print(ch) } 

The output of the above program execution is as follows:

R u n o o b 

9.25.3. String concatenation character #

The following example demonstrates the use of the String of append() method to implement string concatenation characters:

import Cocoa var varA:String = "Hello " let varB:Character = "G" varA.append( varB ) print("varC = \(varA)") 

The output of the above program execution is as follows:

varC = Hello G 