Swift基础语法（二）

操作符

　　swift中运算符基本基础于c，下面我就给大家白话白话那些被优化过的运算符们

//加号减号的妙用
var a=1
var b= -a//此时b=-1
var c = +b//此时 c=-1
var d= - c//此时 d=1

　　操作符

//操作符(数字...数字1)表示从数字到数字1之间的数其中包括数字和数字1
for var i in 1...5{
    printlin("数字：\(i)进化后：\(i*6)")
}
/*输出
数字：1进化后：6
数字：2进化后：12
数字：3进化后：18
数字：4进化后：24
数字：5进化后：30
*/

字符串

　　swift里面用到的字符串默认都是utf-16字符编码，无论是标识符还是自定义字符串

　　字符串拼接用加号（+）

　　字符串遍历用for...in

//字符串拼接
var a="Hello"
var b="world"
var c=" "
println(a+c+b)//输出Hello World
println(a+b)//输出HelloWorld
//字符串遍历
for i in a{
    print("\(i) ")//输出：H e l l o
}
//获取字符串长度countElements
print(countElements(a))//5
//字符串赋值
“let wiseWords = "\"Imagination is more important than knowledge\" - Einstein"
// "Imagination is more important than knowledge" - Einstein
let dollarSign = "\x24"        // $,  Unicode scalar U+0024
let blackHeart = "\u2665"      // ♥,  Unicode scalar U+2665
let sparklingHeart = "\U0001F496"  // 💖, Unicode scalar U+1F496”
var check1:String = "Swift is good!"
var check2:String = "Swift is good!"
//字符串是否相等
if check1 == check2 {
  println("check1 = check2")
} else {
  println("check1 != check2")
}

//是否包含前缀
var preCheck = "Swift"
if check1.hasPrefix(preCheck) {
  println("包含前缀")
}

//是否包含后缀
var sufCheck = "good!"
if check1.hasSuffix(sufCheck) {
  println("包含后缀")
}
//大小写转换
let myString = "Wait a moment, please."
let newString = myString.uppercaseString
// "WAIT A MOMENT, PLEASE."

let myString = "Wait a moment, please."
let newString = myString.lowercaseString
// "wait a moment, please."
//是否包含字符串
var myString = "This is a string test"
if myString.rangeOfString("string") {
    println("exists")
}
//截取字符串
/截取字符串的标识位从1开始计数
let myString = "ABCDEFGHI"

//1.从目标标识位后一个字符开始截取余下的字符串
let mySubstring = (myString.substringFromIndex(2))
println(mySubstring)    // "CDEFGHI"

//2.从第一个字符截取到目标标识位
let mySubstring2 = (myString.substringToIndex(4))
println(mySubstring2)   // "ABCD"
//分割字符串
//单一分隔符:只有一种分割符
var myString = "Berlin, Paris, New York, San Francisco"
//1.隐式定义字符串数组
var myArray = myString.componentsSeparatedByString(",")
//2.显示定义字符串数组
var myArray2 : String[] = myString.componentsSeparatedByString(", ")
for em in myArray2 {
  print(em)   //Berlin Paris New York San
}
//多重分割符:有2个或两个以上分隔符
var myString2 = "One-Two-Three-1 2 3"
var array2:String[] = myString2.componentsSeparatedByCharactersInSet(NSCharacterSet (charactersInString: "- "))
//["One", "Two", "Three", "1", "2", "3"]
//字符串去空格
var newString = myString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
//字符串转NSData
let string: NSString = myString
let data = string.dataUsingEncoding(NSUTF8StringEncoding)

　　字符串转编码

let dogString = "Dog!🐶"
“for codeUnit in dogString.utf8 {
    print("\(codeUnit) ")
}
print("\n")
// 68 111 103 33 240 159 144 182
“for codeUnit in dogString.utf16 {
    print("\(codeUnit) ")
}
print("\n")
// 68 111 103 33 55357 56374”

 

明天Array dictionary