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let string1 = "hello"
let string2 = " there"
var welcome = string1 + string2 // hello there
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let age = 28
let name = "John"
let isAlcoholic = true
var description = "\(name) is \(age) years old and \(isAlcoholic ? "is" : "isn't") alcoholic"
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var greet = "Hello "
var name = "Jack"
// using the append() method
greet.append(name)
print(greet)