swift中操作string

var str
9ad0
1 = “10”

var str2 = “2”

var str3 = str1 + str2 //字符串相加

var age = 10

var hand = 2

var str4 = “I have \(age)
岁了, 有\(hand) 只手”//字符串拼接

var str5 = “I have ” + String(str1) +”岁。”//整形转成字符串