Swift语言特性及基本数据类型
Today ,苹果刚刚发布了Swift语言,我们来看下Swift的几个主要特性:
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1 Safe
func configureLabels(labels: UILabel[]) {
let labelTextColor = UIColor.greenColor()
for label in labels {
// label inferred to be UILabel
label.textColor = labelTextColor
}
}
2 Modern
let cities = ["London", "San Francisco", "Tokyo", "Barcelona", "Sydney"]
let sortedCities = sort(cities) { $0 < $1 }
if let indexOfLondon = find(sortedCities, "London") {
println("London is city number\(indexOfLondon + 1) in the list")
}
3 Powerful:
let size = (20, 40)
switch size {
case let (width, height) where width == height:
println("square with sides\(width)")
case (1..10, 1..10):
println("small rectangle")
case let (width, height):
println("rectangle with width\(width) and height\(height)")
}
4 Interactive
5 Fast。
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基本数据类型:
1 简单属性:
let: 恒定常量
var:可变常量
1.1 定义常量不用指定其固定类型,编译器会处理,如需更多识别,请添加前缀:
let implicitInteger = 70
let implicitDouble = 70.0
let explicitDouble: Double = 70
println("int:\(implicitInteger) double:\(implicitDouble) explicitDoubledss:\(explicitDouble)");
2 类型之间的转化,必须是显示的:
let label ="width is :";
let width = 54;
let widthLabel = label + String(width)
println("LabelWidth:\(widthLabel)");
3 使用反斜杠在String中插入内容,代码参考2
4 使用中括号创建数组和字典:
var shoppingList = ["catfish","water","tulips","blue paint"]
shoppingList[1] ="bottle of water"
var occupations = [
"Malcolm":"Captain",
"Kaylee":"Mechanic",
]
occupations["Jayne"] ="Public Relations"
println("array is\(shoppingList)")
println("dictionary is :\(occupations)")
//create Empty
let emptyArray = String[]()
let emptyDictionary = Dictionary
下一篇文章将介绍控制语句
标题名称:Swift语言特性及基本数据类型
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