Swift 的字符是一個(gè)單一的字符串文字并且是字符數(shù)據(jù)類型。下面是一個(gè)簡單的例子,使用了兩種字符常量:
import Cocoa let char1: Character = "A" let char2: Character = "B" println("Value of char1 \(char1)") println("Value of char2 \(char2)")
當(dāng)上述代碼被編譯和執(zhí)行時(shí),它產(chǎn)生了以下結(jié)果:
Value of char1 A Value of char2 B
如果嘗試存儲多個(gè)字符到字符類型的變量或常量,那么 Swift 是不會允許的。試著鍵入下面的示例到 Swift Playground,在編譯之前,就已經(jīng)會得到一個(gè)錯(cuò)誤。
import Cocoa // Following is wrong in Swift let char: Character = "AB" println("Value of char \(char)")
不可能創(chuàng)建一個(gè)空的字符變量或常量,這將有空值。下面的語法是不可能的:
import Cocoa // Following is wrong in Swift let char1: Character = "" var char2: Character = "" println("Value of char1 \(char1)") println("Value of char2 \(char2)")
當(dāng)討論 Swift 的字符串,字符串表示的字符值按指定順序的集合。因此,我們可以從給定字符串通過 for-in 循環(huán)來遍歷字符串以訪問單個(gè)字符:
import Cocoa for ch in "Hello" { println(ch) }
當(dāng)上述代碼被編譯和執(zhí)行時(shí),它產(chǎn)生了以下結(jié)果:
H e l l o
下面的例子演示了 Swift 字符如何與字符串連接。
import Cocoa var varA:String = "Hello " let varB:Character = "G" varA.append( varB ) println("Value of varC = \(varA)")
當(dāng)上述代碼被編譯和執(zhí)行時(shí),它產(chǎn)生了以下結(jié)果:
Value of varC Hello G