探究苹果技术原理和学习新技术(锲而舍之，朽木不折；锲而不舍，金石可镂。)

1、Initializing an Empty Stringvar emtyString = “”var anotherEmptyString = String()两种初始化方法2、Find out whether a String value is empty by checking its Boolean isEmpty propertyif emptyString.isE

1、Arrays are ordered collections of values.Sets are unordered collections of unique values.Dictionaries are unordered collections of key-value associations(键值关联)（数组有序，set无序，dic也没有序号）2、如果创建的array、set

文档地址：https://developer.apple.com/library/prerelease/content/documentation/Swift/Conceptual/Swift_Programming_Language/BasicOperators.html#//apple_ref/doc/uid/TP40014097-CH6-ID601、swift support