小编job*_*r80的帖子

我是学习Swift的新手,所以我决定不再学习Swift 2.到目前为止,除了以下代码片段之外,一切对我都有意义.希望有人可以为我阐明这一点.

//: Playground - noun: a place where people can play
import UIKit

//Works
let possibleNumber="2"
if let actualNumber = Int(possibleNumber) {
    print("\'\(possibleNumber)\' has an integer value of \(actualNumber)")
}
else {
    print("could not be converted to integer")
}

//Doesn't Work and I'm not sure why
let testTextField = UITextField()
testTextField.text = "2"
let numberString = testTextField.text  //I know this is redundant

if let num = Int(numberString) {
    print("The number is: \(num)")
}
else {
    print("Could not be converted …