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1、swift supports most standard C operators
swfit语言支持大部分c语言的预算符号
2、swift also provides two range operators (a..b and a…b)not found in C
范围符号
3、if the right side of the assignment is a tuple with multiple values,its elements can be decomposed into multiple constants or vairables at once:
let (x,y) = (1,2)
4、Unlike the assignment operator in C and Objective-C,the assignment operator in swift does not itself return a value.
不像c语言或者oc语言，在swift中的赋值运算符不返回一个值
The following statement is not valid
if x = y {
}
5、arithmetic opetators数学运算符
6、The addition opetater is also supported For String concatnecation.
“hello” + “world”
7、Swift supports all standard C comparison opetators
(==,!=,>)等
8、Swfit also provides two identify operators(=== and !==),which you use to test whether two object references both refer to the same object instance.
用===和！==来测试两个对象指向相同的实例
9、Tuple也能比较，the comparison is already determined by the tuples’ fisrt elements.
如果第一个元素相同，继续看后面的元素
10、Use the ternary conditional operator with care,however.its consiceness can lead to hard-to-read code if overused.Avoid combning multiple instances of the ternary conditional opetator into one compound statement
三元运算符不能滥用，尽量避免将几个三元运算符放进一个复合的语句
11、nil_coalescing Operator
a??b相当于
a != nil ? a! :b
let defaultColorName = “Red”
var userDefinedColorName:String?
var colorNameToUse = userDefinedColorName ??defaultColorName
12、Range Operators
closed Range Operator
range operator(a…b)defines a ranges that runs from a to b,and inludes the values a and b.
for index in 1…5 {
print(“\(index) times 5 is \(index * 5)”)
}
Half-Open Range Operator
The half-open range operator(a..<b) which does not include b
13、logical Operators
!,&&,||
