Get file size in Swift

Use attributesOfItemAtPath instead of attributesOfFileSystemForPath + call .fileSize() on your attr.

var filePath: NSString = "your path here"
var fileSize : UInt64
var attr:NSDictionary? = NSFileManager.defaultManager().attributesOfItemAtPath(filePath, error: nil)
if let _attr = attr {
    fileSize = _attr.fileSize();
}

In Swift 2.0, we use do try catch pattern, like this:

let filePath = "your path here"
var fileSize : UInt64 = 0

do {
    let attr : NSDictionary? = try NSFileManager.defaultManager().attributesOfItemAtPath(filePath)

    if let _attr = attr {
        fileSize = _attr.fileSize();
    }
} catch {
    print("Error: \(error)")
}

In Swift 3.x/4.0:

let filePath = "your path here"
var fileSize : UInt64

do {
    //return [FileAttributeKey : Any]
    let attr = try FileManager.default.attributesOfItem(atPath: filePath)
    fileSize = attr[FileAttributeKey.size] as! UInt64

    //if you convert to NSDictionary, you can get file size old way as well.
    let dict = attr as NSDictionary
    fileSize = dict.fileSize()
} catch {
    print("Error: \(error)")
}

In Swift 3+ you can get the file size directly from the URL, (NS)FileManager is not needed. And ByteCountFormatter is a smart way to display the file size.

let url = Bundle.main.url(forResource:"movie", withExtension: "mov")!
do {
    let resourceValues = try url.resourceValues(forKeys: [.fileSizeKey])
    let fileSize = resourceValues.fileSize!
    print("File size = " + ByteCountFormatter().string(fromByteCount: Int64(fileSize)))
} catch { print(error) }

Actually you can get the file size from the URL even in Swift 2 but the syntax is a bit more cumbersome.

Swift4: URL extension to easily access file attributes

Extension:

extension URL {
    var attributes: [FileAttributeKey : Any]? {
        do {
            return try FileManager.default.attributesOfItem(atPath: path)
        } catch let error as NSError {
            print("FileAttribute error: \(error)")
        }
        return nil
    }

    var fileSize: UInt64 {
        return attributes?[.size] as? UInt64 ?? UInt64(0)
    }

    var fileSizeString: String {
        return ByteCountFormatter.string(fromByteCount: Int64(fileSize), countStyle: .file)
    }

    var creationDate: Date? {
        return attributes?[.creationDate] as? Date
    }
}

Usage:

let fileUrl: URL
print("file size = \(fileUrl.fileSize), \(fileUrl.fileSizeString)")

SWIFT 3 come from @Hoa's answer and plus a function let UInt64 to readable String.

func sizeForLocalFilePath(filePath:String) -> UInt64 {
    do {
        let fileAttributes = try FileManager.default.attributesOfItem(atPath: filePath)
        if let fileSize = fileAttributes[FileAttributeKey.size]  {
            return (fileSize as! NSNumber).uint64Value
        } else {
            print("Failed to get a size attribute from path: \(filePath)")
        }
    } catch {
        print("Failed to get file attributes for local path: \(filePath) with error: \(error)")
    }
    return 0
}
func covertToFileString(with size: UInt64) -> String {
    var convertedValue: Double = Double(size)
    var multiplyFactor = 0
    let tokens = ["bytes", "KB", "MB", "GB", "TB", "PB",  "EB",  "ZB", "YB"]
    while convertedValue > 1024 {
        convertedValue /= 1024
        multiplyFactor += 1
    }
    return String(format: "%4.2f %@", convertedValue, tokens[multiplyFactor])
}