Remove last character from string. Swift language

Question

How can I remove last character from String variable using Swift? Can\'t find it in documentation.

Here is full example:

var expression = \"45+22\"
e         


        

Answer 1

complimentary to the above code I wanted to remove the beginning of the string and could not find a reference anywhere. Here is how I did it:

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

This trims 17 characters from the beginning of the string (he total string length is 67 we advance -50 from the end and there you have it.

Answer 2

The dropLast() function removes the last element of the string.

var expression = "45+22"
expression = expression.dropLast()

Answer 3

The global dropLast() function works on sequences and therefore on Strings:

var expression  = "45+22"
expression = dropLast(expression)  // "45+2"

// in Swift 2.0 (according to cromanelli's comment below)
expression = String(expression.characters.dropLast())

Answer 4

Swift 3 (according to the docs) 20th Nov 2016

let range = expression.index(expression.endIndex, offsetBy: -numberOfCharactersToRemove)..<expression.endIndex
expression.removeSubrange(range)

Answer 5

var str = "Hello, playground"

extension String {
    var stringByDeletingLastCharacter: String {
        return dropLast(self)
    }
}

println(str.stringByDeletingLastCharacter)   // "Hello, playgroun"

Answer 6

A swift category that's mutating:

extension String {
    mutating func removeCharsFromEnd(removeCount:Int)
    {
        let stringLength = count(self)
        let substringIndex = max(0, stringLength - removeCount)
        self = self.substringToIndex(advance(self.startIndex, substringIndex))
    }
}

Use:

var myString = "abcd"
myString.removeCharsFromEnd(2)
println(myString) // "ab"