我知道如何通过编程来做到这一点,但我相信有一种内置的方式……
我使用过的每种语言都有某种对象集合的默认文本表示,当您试图将Array与字符串连接起来或将其传递给print()函数等时,它会吐出这些文本表示。苹果的Swift语言是否有一种内置的方式,可以轻松地将数组转换为字符串,或者我们总是必须显式地对数组进行字符串化?
我知道如何通过编程来做到这一点,但我相信有一种内置的方式……
我使用过的每种语言都有某种对象集合的默认文本表示,当您试图将Array与字符串连接起来或将其传递给print()函数等时,它会吐出这些文本表示。苹果的Swift语言是否有一种内置的方式,可以轻松地将数组转换为字符串,或者我们总是必须显式地对数组进行字符串化?
当前回答
对于swift 3:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if textField == phoneField
{
let newString = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
let components = newString.components(separatedBy: NSCharacterSet.decimalDigits.inverted)
let decimalString = NSString(string: components.joined(separator: ""))
let length = decimalString.length
let hasLeadingOne = length > 0 && decimalString.character(at: 0) == (1 as unichar)
if length == 0 || (length > 10 && !hasLeadingOne) || length > 11
{
let newLength = NSString(string: textField.text!).length + (string as NSString).length - range.length as Int
return (newLength > 10) ? false : true
}
var index = 0 as Int
let formattedString = NSMutableString()
if hasLeadingOne
{
formattedString.append("1 ")
index += 1
}
if (length - index) > 3
{
let areaCode = decimalString.substring(with: NSMakeRange(index, 3))
formattedString.appendFormat("(%@)", areaCode)
index += 3
}
if length - index > 3
{
let prefix = decimalString.substring(with: NSMakeRange(index, 3))
formattedString.appendFormat("%@-", prefix)
index += 3
}
let remainder = decimalString.substring(from: index)
formattedString.append(remainder)
textField.text = formattedString as String
return false
}
else
{
return true
}
}
其他回答
对于swift 3:
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
if textField == phoneField
{
let newString = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
let components = newString.components(separatedBy: NSCharacterSet.decimalDigits.inverted)
let decimalString = NSString(string: components.joined(separator: ""))
let length = decimalString.length
let hasLeadingOne = length > 0 && decimalString.character(at: 0) == (1 as unichar)
if length == 0 || (length > 10 && !hasLeadingOne) || length > 11
{
let newLength = NSString(string: textField.text!).length + (string as NSString).length - range.length as Int
return (newLength > 10) ? false : true
}
var index = 0 as Int
let formattedString = NSMutableString()
if hasLeadingOne
{
formattedString.append("1 ")
index += 1
}
if (length - index) > 3
{
let areaCode = decimalString.substring(with: NSMakeRange(index, 3))
formattedString.appendFormat("(%@)", areaCode)
index += 3
}
if length - index > 3
{
let prefix = decimalString.substring(with: NSMakeRange(index, 3))
formattedString.appendFormat("%@-", prefix)
index += 3
}
let remainder = decimalString.substring(from: index)
formattedString.append(remainder)
textField.text = formattedString as String
return false
}
else
{
return true
}
}
在Swift 4中
let array:[String] = ["Apple", "Pear ","Orange"]
array.joined(separator: " ")
如果你有字符串数组列表,那么转换为Int
let arrayList = list.map { Int($0)!}
arrayList.description
它会给你字符串值
你可以使用循环来完成这个任务。或者使用地图。
通过映射:
let array = ["one" , "two" , "three"]
array.map({$0}).joined(seperator : ",")
在分隔符中,你可以修改字符串。
Output-> ("one,two,three")
当你也有struct数组时,你可以使用joined()来获得单个String。
struct Person{
let name:String
let contact:String
}
使用map() & joined()可以轻松生成字符串
PersonList.map({"\($0.name) - \($0.contact)"}).joined(separator: " | ")
输出:
Jhon - 123 | Mark - 456 | Ben - 789