我如何从字符串变量使用Swift删除最后一个字符?在文档中找不到。
下面是完整的例子:
var expression = "45+22"
expression = expression.substringToIndex(countElements(expression) - 1)
当前回答
斯威夫特4/5
var str = "bla"
str.removeLast() // returns "a"; str is now "bl"
其他回答
使用函数removeAtIndex(i: String.Index)
var s = "abc"
s.removeAtIndex(s.endIndex.predecessor()) // "ab"
补充上述代码，我想删除字符串的开头，但在任何地方都找不到引用。以下是我的做法:
var mac = peripheral.identifier.description
let range = mac.startIndex..<mac.endIndex.advancedBy(-50)
mac.removeRange(range) // trim 17 characters from the beginning
let txPower = peripheral.advertisements.txPower?.description
这将从字符串的开头修剪17个字符(字符串的总长度是67，从末尾向前移动-50，就得到了它。
一个快速变化的类别:
extension String {
mutating func removeCharsFromEnd(removeCount:Int)
{
let stringLength = count(self)
let substringIndex = max(0, stringLength - removeCount)
self = self.substringToIndex(advance(self.startIndex, substringIndex))
}
}
使用:
var myString = "abcd"
myString.removeCharsFromEnd(2)
println(myString) // "ab"
let str = "abc"
let substr = str.substringToIndex(str.endIndex.predecessor()) // "ab"
斯威夫特4
var welcome = "Hello World!"
welcome = String(welcome[..<welcome.index(before:welcome.endIndex)])
or
welcome.remove(at: welcome.index(before: welcome.endIndex))
or
welcome = String(welcome.dropLast())
