Check out example codes for "swift get app version and build". It will help you in understanding the concepts better.

Code Example 1

import Foundation

extension Bundle {

    var shortVersion: String {
        if let result = infoDictionary?["CFBundleShortVersionString"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    var buildVersion: String {
        if let result = infoDictionary?["CFBundleVersion"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    var fullVersion: String {
        return "\(shortVersion)(\(buildVersion))"
    }
}

// Usage:

someLabel.text = Bundle.main.versionNumber

Code Example 2

let appVersion = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String

Code Example 3

import Foundation

extension Bundle {

    var shortVersion: String {
        if let result = infoDictionary?["CFBundleShortVersionString"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    var buildVersion: String {
        if let result = infoDictionary?["CFBundleVersion"] as? String {
            return result
        } else {
            assert(false)
            return ""
        }
    }

    var fullVersion: String {
        return "\(shortVersion)(\(buildVersion))"
    }
}

// Usage:

someLabel.text = Bundle.main.versionNumber

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