我也知道这个问题已经有了答案，但我总结了之前的答案:

(*)扩展更新

extension Bundle {
    var releaseVersionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }
    var buildVersionNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }
    var releaseVersionNumberPretty: String {
        return "v\(releaseVersionNumber ?? "1.0.0")"
    }
}

用法:

someLabel.text = Bundle.main.releaseVersionNumberPretty

@Deprecated:旧答案

斯威夫特3.1:

class func getVersion() -> String {
    guard let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String else {
        return "no version info"
    }
    return version
}

对于旧版本:

class func getVersion() -> String {
    if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String {
        return version
    }
    return "no version info"
}

如果你想设置标签文本或者想在其他地方使用;

self.labelVersion.text = getVersion()

我在捆绑上做了一个扩展

extension Bundle {

    var appName: String {
        return infoDictionary?["CFBundleName"] as! String
    }

    var bundleId: String {
        return bundleIdentifier!
    }

    var versionNumber: String {
        return infoDictionary?["CFBundleShortVersionString"] as! String 
    }

    var buildNumber: String {
        return infoDictionary?["CFBundleVersion"] as! String
    }

}

然后使用它

versionLabel.text = "\(Bundle.main.appName) v \(Bundle.main.versionNumber) (Build \(Bundle.main.buildNumber))"

鉴于Swift一直在发展，我的回答(截至2015年8月):

let version = NSBundle.mainBundle().infoDictionary!["CFBundleVersion"] as! String

Xcode 8, Swift 3:

let gAppVersion = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") ?? "0"
let gAppBuild = Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion") ?? "0"

捆绑+扩展.swift

import Foundation

extension Bundle {
    var versionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }

    var buildNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }

    var bundleName: String? {
        return infoDictionary?["CFBundleName"] as? String
    }
}

用法:

someLabel.text = Bundle.main.versionNumber

以下是Swift 3.2的更新版本:

extension UIApplication
{
    static var appVersion:String
    {
        if let appVersion = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString")
        {
            return "\(appVersion)"
        }
        return ""
    }

    static var buildNumber:String
    {
        if let buildNum = Bundle.main.object(forInfoDictionaryKey: kCFBundleVersionKey as String)
        {
            return "\(buildNum)"
        }
        return ""
    }

    static var versionString:String
    {
        return "\(appVersion).\(buildNumber)"
    }
}