I have the following error:
Type 'DispatchQueue' has no member 'GlobalAttributes'
In my code. Do you know why?
public typealias Classification = (Label: DigitLabel, Confidence: CGFloat, BestPrototypeIndex: Int)
public func classifyDigit(digit: DigitStrokes, votesCounted: Int = 5, scoreCutoff: CGFloat = 0.8) -> Classification? {
if let normalizedDigit = normalizeDigit(inputDigit: digit) {
let serviceGroup = DispatchGroup()
let queue = ***DispatchQueue.global(attributes: DispatchQueue.GlobalAttributes.qosUserInitiated)***
let serialResultsQueue = DispatchQueue(label: "collect_results")
var bestMatches = SortedMinArray<CGFloat, (DigitLabel, Int)>(capacity: votesCounted)
for (label, prototypes) in self.normalizedPrototypeLibrary {
queue.async(group: serviceGroup) {
var localBestMatches = SortedMinArray<CGFloat, (DigitLabel, Int)>(capacity: votesCounted)
var index = 0
for prototype in prototypes {
if prototype.count == digit.count {
let score = self.classificationScore(sample: normalizedDigit, prototype: prototype)
//if score < scoreCutoff {
localBestMatches.add(value: score, element: (label, index))
//}
}
index += 1
}
serialResultsQueue.async(group: serviceGroup) {
for (score, bestMatch) in localBestMatches {
bestMatches.add(value: score, element: bestMatch)
}
}
}
}
I also attached the file, just in case.
According to Apple's documentation, the message is correct.
Maybe you want to use DispatchQueue.Attributes?
EDIT:
I just had a closer look at the documentation:
DispatchQueue.global() seems to be changed. The documentation shows this declaration:
class func global(qos: DispatchQoS.QoSClass = default) -> DispatchQueue
I tested some variations, Xcode proposed and found this line:
let queue = DispatchQueue.global(qos: DispatchQoS.QoSClass.userInitiated)
I did not test, if this works 100% with your example, but Xcode will compile it
Related
I have the following array:
var notebookCovers = ["cover1", "cover2", "cover3", "cover4", "cover4", "cover6", "cover7", "cover8", "cover9", "cover10"]
and a UIButton that when it's pressed it generates a new UIImage with one of the elements of the array.
What I need to do is every time the button is tapped to generate random but unique element from the array (without repeating the elements) until they've all been selected and then restart the array again.
So far, I have it getting a random element but it's repeated and I cannot figure out how to it so it gets a unique image every time
func createNewNotebook() {
let newNotebook = Notebook()
let randomInt = randomNumber()
newNotebook.coverImageString = notebookCovers[randomInt]
notebooks.insert(newNotebook, at: 0)
collectionView.reloadData()
}
func randomNumber() -> Int {
var previousNumber = arc4random_uniform(UInt32(notebookCovers.count))
var randomNumber = arc4random_uniform(UInt32(notebookCovers.count - 1))
notebookCovers.shuffle()
if randomNumber == previousNumber {
randomNumber = UInt32(notebookCovers.count - 1)
}
previousNumber = randomNumber
return Int(randomNumber)
}
Set is a collection type that holds unique elements. Converting your notebooks array to Set also lets you take advantage of its randomElement function
var aSet = Set(notebooks)
let element = aSet.randomElement()
aSet.remove(element)
Copy the array. Shuffle the copy. Now just keep removing the first element until the copy is empty. When it is empty, start over.
Example:
let arr = [1,2,3,4,5]
var copy = [Int]()
for _ in 1...30 { // just to demonstrate what happens
if copy.isEmpty { copy = arr; copy.shuffle() }
let element = copy.removeFirst() ; print(element, terminator:" ")
}
// 4 2 3 5 1 1 5 3 2 4 4 1 2 3 5 1 4 5 2 3 3 5 4 2 1 3 2 4 5 1
If you want to create a looping solution:
let originalSet = Set(arrayLiteral: "a","b","c")
var selectableSet = originalSet
func repeatingRandomObject() -> String {
if selectableSet.isEmpty {
selectableSet = originalSet
}
return selectableSet.remove(selectableSet.randomElement()!)!
}
force unwrapping is kind of safe here, since we know that the result will never be nil. If you don't want to force unwrap:
let originalSet = Set(arrayLiteral: "a","b","c")
var selectableSet = originalSet
func repeatingRandomObject() -> String? {
if selectableSet.isEmpty {
selectableSet = originalSet
}
guard let randomElement = selectableSet.randomElement() else { return nil }
return selectableSet.remove(randomElement)
}
You can try something like this,
var notebookCovers = ["cover1", "cover2", "cover3", "cover4", "cover4", "cover6", "cover7", "cover8", "cover9", "cover10"]
var tappedNotebooks: [String] = []
func tapping() {
let notebook = notebookCovers[Int.random(in: 0...notebookCovers.count - 1)]
if tappedNotebooks.contains(notebook){
print("already exists trying again!")
tapping()
} else {
tappedNotebooks.append(notebook)
print("appended", notebook)
}
if tappedNotebooks == notebookCovers {
tappedNotebooks = []
print("cleared Tapped notebooks")
}
}
It is possible with shuffle:
struct AnantShuffler<Base: MutableCollection> {
private var collection: Base
private var index: Base.Index
public init?(collection: Base) {
guard !collection.isEmpty else {
return nil
}
self.collection = collection
self.index = collection.startIndex
}
public mutating func next() -> Base.Iterator.Element {
let result = collection[index]
collection.formIndex(after: &index)
if index == collection.endIndex {
collection.shuffle()
index = collection.startIndex
}
return result
}
}
fileprivate extension MutableCollection {
/// Shuffles the contents of this collection.
mutating func shuffle() {
let c = count
guard c > 1 else { return }
for (firstUnshuffled, unshuffledCount) in zip(indices, stride(from: c, to: 1, by: -1)) {
let d: Int = numericCast(arc4random_uniform(numericCast(unshuffledCount)))
let i = index(firstUnshuffled, offsetBy: d)
swapAt(firstUnshuffled, i)
}
}
}
Use:
let shuffler = AnantShuffler(collection: ["c1","c2","c3"].shuffled())
shuffler?.next()
I'm developing a music sequencer with a standard piano roll type UI.
It was working well until I made some changes in the model side but it suddenly started to report EXC_BAD_ACCESS at (seemingly) unrelated part.
What's strange is all the necessary variables have their values properly and actually I can print values with po.
In my understanding, EXC_BAD_ACCESS happens when an object doesn't exist, so this seems quite strange.
My question is:
Is it common to EXC_BAD_ACCESS even the values are there?
If that's the case what is the possible situation to cause that?
Any suggestion is helpful. Thanks
[Below are the codes]
In my subclass of UICollectionViewLayout:
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
// note cells
let cv = self.collectionView as! YMPianoRollCollectionView;
let pianoRoll = cv.pianoRollViewController;
// Call the below func to get the indexes of the Note Objects included in the specified rect
let indexArray: Array<Int> = pianoRoll!.getNoteIndexes(inRect:rect, useOnlyStartTime: false);
var retArray : [UICollectionViewLayoutAttributes] = []
for i in indexArray {
if let _ = pianoRoll?.pattern.eventSequence[i] as? YMPatternEventNoteOn {
retArray.append( self.layoutAttributesForPatternEventInfo(i) )
}
}
return retArray
}
In my "piano roll" class which contains UICollectionView
func getNoteIndexes(inRect rect:CGRect, useOnlyStartTime: Bool) -> Array<Int> {
//
// Transform given values into musical values
//
let musicRange :YMMusicalValueRange = screenInfo.getMusicalRange(rect);
let startTime = musicRange.origin.time;
let endTime = musicRange.origin.time + musicRange.size.timeLength;
let lowNoteU = musicRange.origin.noteNumber;
let highNoteU = musicRange.origin.noteNumber + musicRange.size.numberOfNotes;
var retArray : [Int] = []
for i in 0..<pattern.eventSequence.count {
if let e = pattern.eventSequence[i] as? YMPatternEventNoteOn {
//
// Prepare ranges
//
let noteNo = e.noteNo; //<- App Crashes Here with BAD_ACCESS
let noteStTime = e.time;
let noteEnTime = e.time + e.duration;
let targetNoteRange = Range<Int>(uncheckedBounds: (lowNoteU, highNoteU));
let targetTimeRange = Range<Int64>(uncheckedBounds: (startTime, endTime))
let noteTimeRange = Range<Int64>(uncheckedBounds: (noteStTime, noteEnTime))
//
// Check the match
//
let noteMatches = targetNoteRange.contains(noteNo);
let timeMatches = useOnlyStartTime ? targetTimeRange.contains(noteStTime)
: targetTimeRange.overlaps(noteTimeRange)
if noteMatches && timeMatches {
retArray.append( i );
NSLog("XXX Found: note \(noteNo) at \(e.time)");
}
}
}
return retArray;
}
Error:- The object states when it crashed
EDIT
Here's the YMPatternEventNoteOn declaration
class YMPatternEvent : Codable, CustomDebugStringConvertible {
var time : YMSequenceTime = 0
// Some utility funcs follow
// ...
}
class YMPatternEventNoteOn : YMPatternEvent {
var noteNo : Int = 64
var velocity : Int = 127
var duration : YMSequenceTime = 480
var tempBendId : Int = 0;
var tempVibratoId : Int = 0;
var tempArpeggioId : Int = 0;
convenience init(time :YMSequenceTime, noteNo : Int, velocity: Int, duration: YMSequenceTime) {
self.init();
self.time = time;
self.noteNo = noteNo;
self.velocity = velocity;
self.duration = duration;
}
// Other methods follow
// ...
}
EDIT2
Note event is created by the user's action
//
// In YMPattern object
//
func insertNote(time:YMSequenceTime, noteNo:Int, velocity:Int, duration:YMSequenceTime) -> Int
{
let onEvent = YMPatternEventNoteOn(time: time, noteNo: noteNo, velocity: velocity, duration: duration);
let retIndex = insertEvent(onEvent);
return retIndex;
}
func insertEvent(_ event: YMPatternEvent) -> Int {
let atTime = event.time;
var retIndex : Int = 0;
if(eventSequence.count<1){
// If it's the first event just add it
eventSequence.append(event);
retIndex = 0;
} else {
// If any event already exists, insert with time order in consideration
var i : Int = 0;
while( atTime > eventSequence[i].time ){
i += 1;
if( i >= eventSequence.count ){
break;
}
}
retIndex = i;
eventSequence.insert(event, at: i)
}
}
//
// In pianoroll view controller
//
func actionButtonReleased(afterDragging: Bool) {
let values:YMMusicalValuePoint = screenInfo.getMusicalPosition(cursorPosition);
// insert new event with default velocity and duration
let _ = pattern.insertNote(time: values.time, noteNo: values.noteNumber, velocity: 127, duration: screenInfo.timeTicsPerDivision());
collectionView.reloadData();
}
I've solved it in a way.
By setting the optimization level to "Whole Module Optimization" it stopped reporting the error.
I don't know what is happening internally but if someone is having the same issue, this might work as a quick fix.
Hey I'm trying to figure out how to tally up soccer goals on the condition that the goal was scored in under 45 minutes, but the func has some slight errors with swift 2. Any help? Thanks!
Code:
var barcelonavsRealMadrid1goals : [String : Int] = ["barcelonaGoal1":21,"RealMadridGoal2":23,"barcelonaGoal3":24,"RealMadridGoal4":27]
func Run() {
var goalCount=0
for (goal,numbers) in barcelonavsRealMadrid1goals{
for(var number in numbers) {
if(number < 45)
goalCount++
}
}
You have an extra for..in loop in there that's not needed:
for(var number in numbers) {
It also has an extraneous ( and ) around it
for var number in numbers {
Here is a working version of your code:
var barcelonavsRealMadrid1goals = ["barcelonaGoal1":21,"RealMadridGoal2":23,"barcelonaGoal3":24,"RealMadridGoal4":27]
func run() -> Int { // functions should start with lower case
var goalCount=0
for (_,numbers) in barcelonavsRealMadrid1goals where numbers < 45 {
goalCount++
}
return goalCount
}
let goalCount = run()
And the functional way would be something like:
let goalCount = goals.reduce(0) {
if $0.1.1 < 45 {
return $0.0 + 1
}
return $0.0
}
With explanation:
var goals = [
"barcelonaGoal1" :21,
"RealMadridGoal2":23,
"barcelonaGoal3" :24,
"RealMadridGoal4":27,
"RealMadridGoal5":45]
// For our use reduce takes an initial value of Int
// and a combine function of type
// (Int, (String, Int)) -> Int
//
// Reduce will call the closure once with
// each value in the map and the previous return value
let goalCount = goals.reduce(0, combine: {
(initial:Int, current:(key:String, value:Int)) -> Int in
var currentCount = initial
// print to show input and output of closure
print( "parameters:(\(initial), (\"\(current.key)\", \(current.value)))", terminator:", ")
defer {
print("return:\(currentCount)")
}
// end printing
if current.value < 45 {
++currentCount // add 1 to the running total
return currentCount
}
return currentCount
})
// console output:
// parameters:(0, ("barcelonaGoal1", 21)), return:1
// parameters:(1, ("RealMadridGoal4", 27)), return:2
// parameters:(2, ("RealMadridGoal5", 45)), return:2
// parameters:(2, ("RealMadridGoal2", 23)), return:3
// parameters:(3, ("barcelonaGoal3", 24)), return:4
For solving of you're problem try to use functional programing that is introduced in swift :
var barcelonavsRealMadrid1goals : [String : Int] = ["barcelonaGoal1":95,"RealMadridGoal2":23,"barcelonaGoal3":24,"RealMadridGoal4":27]
var filtered = barcelonavsRealMadrid1goals.filter { (team:String, minute:Int) -> Bool in
var state = false
if (minute > 45)
{
return true
}
return state
}
let totalCount = filtered.count
Try this method.
func Run() {
var goalCount=0
for (_, score) in barcelonavsRealMadrid1goals {
if(score < 45) {
goalCount++
}
}
print(goalCount)
}
Yesterday I have switched my IOS Swift project to the new XCode 6.3 and Swift 1.2. I have so far got everything to build nicely, but at one point the app crashes with the error message "fatal error: array element cannot be bridged to Objective-C" at a line that looks like this:
let services = services as! [ServiceObject]
I have read that the error is because I have Objective C objects as members in the Swift Array which is now not automatically bridged to NSArray anymore, so I would have to either make my objects of type ServiceObject non-Obj-C or declare "services" as an NSArray. The strange thing is that ServiceObject is not an Objective-C object. This is the declaration of the class:
class ServiceObject: MonitoringObject {
let serviceDescription: String
let host: HostObject
var duration = 0
var plugin_output = ""
var active_checks_enabled = 0
var display_name = ""
var has_been_checked = 0
var acknowledged = 0
var acknowledgement_type = 0
var scheduled_downtime_depth = 0
var is_flapping = 0
var state = ServiceState.OK
var name: String {
return serviceDescription
}
init(serviceDescription: String, host: HostObject) {
self.host = host
self.serviceDescription = serviceDescription
}
var durationText: String {
if duration == -1 || duration == 0{
return "N/A"
} else if duration > 86400 {
let days = Int(floor(Float(duration) / 86400))
let hours = Int(floor(Float(duration % 86400) / 3600))
return "\(days)d, \(hours)h"
} else if duration > 3600 {
let hours = Int(floor(Float(duration) / 3600))
let minutes = Int(floor(Float(duration) % 3600 / 60))
return "\(hours)h, \(minutes)m"
} else if duration > 60 {
let minutes = Int(floor(Float(duration) / 60))
let seconds = duration % 60
return "\(minutes)m, \(seconds)s"
} else {
return "\(duration)s"
}
}
}
Also, the protocol "MonitoringObject" which ServiceObject conforms to is not Obj-C:
protocol MonitoringObject {
var name: String { get }
}
Does anybody have any clue where the error and the crash come from?
Edit: this is the whole method where the line that fails is contained, to make the context more clear:
private func buildHostServicesIndex(services: [MonitoringObject]) -> [HostServicesEntry] {
//typealias HostServicesEntry = (HostObject, [ServiceObject])
let services = services as! [ServiceObject]
let hosts = services.map {
(service) -> HostObject in
service.host
}
let distinctHosts = Helpers.distinct(hosts)
return distinctHosts.map {
(host) -> HostServicesEntry in
return (host, services.filter {
(service) -> Bool in
service.host == host
})
}
}
I need to create a String with format which can convert Int, Int64, Double, etc types into String. Using Objective-C, I can do it by:
NSString *str = [NSString stringWithFormat:#"%d , %f, %ld, %#", INT_VALUE, FLOAT_VALUE, DOUBLE_VALUE, STRING_VALUE];
How to do same but in Swift?
I think this could help you:
import Foundation
let timeNow = time(nil)
let aStr = String(format: "%#%x", "timeNow in hex: ", timeNow)
print(aStr)
Example result:
timeNow in hex: 5cdc9c8d
nothing special
let str = NSString(format:"%d , %f, %ld, %#", INT_VALUE, FLOAT_VALUE, LONG_VALUE, STRING_VALUE)
let str = "\(INT_VALUE), \(FLOAT_VALUE), \(DOUBLE_VALUE), \(STRING_VALUE)"
Update: I wrote this answer before Swift had String(format:) added to it's API. Use the method given by the top answer.
No NSString required!
String(format: "Value: %3.2f\tResult: %3.2f", arguments: [2.7, 99.8])
or
String(format:"Value: %3.2f\tResult: %3.2f", 2.7, 99.8)
I would argue that both
let str = String(format:"%d, %f, %ld", INT_VALUE, FLOAT_VALUE, DOUBLE_VALUE)
and
let str = "\(INT_VALUE), \(FLOAT_VALUE), \(DOUBLE_VALUE)"
are both acceptable since the user asked about formatting and both cases fit what they are asking for:
I need to create a string with format which can convert int, long, double etc. types into string.
Obviously the former allows finer control over the formatting than the latter, but that does not mean the latter is not an acceptable answer.
First read Official documentation for Swift language.
Answer should be
var str = "\(INT_VALUE) , \(FLOAT_VALUE) , \(DOUBLE_VALUE), \(STRING_VALUE)"
println(str)
Here
1) Any floating point value by default double
EX.
var myVal = 5.2 // its double by default;
-> If you want to display floating point value then you need to explicitly define such like a
EX.
var myVal:Float = 5.2 // now its float value;
This is far more clear.
let INT_VALUE=80
let FLOAT_VALUE:Double= 80.9999
let doubleValue=65.0
let DOUBLE_VALUE:Double= 65.56
let STRING_VALUE="Hello"
let str = NSString(format:"%d , %f, %ld, %#", INT_VALUE, FLOAT_VALUE, DOUBLE_VALUE, STRING_VALUE);
println(str);
The accepted answer is definitely the best general solution for this (i.e., just use the String(format:_:) method from Foundation) but...
If you are running Swift ≥ 5, you can leverage the new StringInterpolationProtocol protocol to give yourself some very nice syntax sugar for common string formatting use cases in your app.
Here is how the official documentation summarizes this new protocol:
Represents the contents of a string literal with interpolations while it’s being built up.
Some quick examples:
extension String.StringInterpolation {
/// Quick formatting for *floating point* values.
mutating func appendInterpolation(float: Double, decimals: UInt = 2) {
let floatDescription = String(format: "%.\(decimals)f%", float)
appendLiteral(floatDescription)
}
/// Quick formatting for *hexadecimal* values.
mutating func appendInterpolation(hex: Int) {
let hexDescription = String(format: "0x%X", hex)
appendLiteral(hexDescription)
}
/// Quick formatting for *percents*.
mutating func appendInterpolation(percent: Double, decimals: UInt = 2) {
let percentDescription = String(format: "%.\(decimals)f%%", percent * 100)
appendLiteral(percentDescription)
}
/// Formats the *elapsed time* since the specified start time.
mutating func appendInterpolation(timeSince startTime: TimeInterval, decimals: UInt = 2) {
let elapsedTime = CACurrentMediaTime() - startTime
let elapsedTimeDescription = String(format: "%.\(decimals)fs", elapsedTime)
appendLiteral(elapsedTimeDescription)
}
}
which could be used as:
let number = 1.2345
"Float: \(float: number)" // "Float: 1.23"
"Float: \(float: number, decimals: 1)" // "Float: 1.2"
let integer = 255
"Hex: \(hex: integer)" // "Hex: 0xFF"
let rate = 0.15
"Percent: \(percent: rate)" // "Percent: 15.00%"
"Percent: \(percent: rate, decimals: 0)" // "Percent: 15%"
let startTime = CACurrentMediaTime()
Thread.sleep(forTimeInterval: 2.8)
"∆t was \(timeSince: startTime)" // "∆t was 2.80s"
"∆t was \(timeSince: startTime, decimals: 0)" // "∆t was 3s"
This was introduced by SE-0228, so please be sure to read the original proposal for a deeper understanding of this new feature. Finally, the protocol documentation is helpful as well.
I know a lot's of time has passed since this publish, but I've fallen in a similar situation and create a simples class to simplify my life.
public struct StringMaskFormatter {
public var pattern : String = ""
public var replecementChar : Character = "*"
public var allowNumbers : Bool = true
public var allowText : Bool = false
public init(pattern:String, replecementChar:Character="*", allowNumbers:Bool=true, allowText:Bool=true)
{
self.pattern = pattern
self.replecementChar = replecementChar
self.allowNumbers = allowNumbers
self.allowText = allowText
}
private func prepareString(string:String) -> String {
var charSet : NSCharacterSet!
if allowText && allowNumbers {
charSet = NSCharacterSet.alphanumericCharacterSet().invertedSet
}
else if allowText {
charSet = NSCharacterSet.letterCharacterSet().invertedSet
}
else if allowNumbers {
charSet = NSCharacterSet.decimalDigitCharacterSet().invertedSet
}
let result = string.componentsSeparatedByCharactersInSet(charSet)
return result.joinWithSeparator("")
}
public func createFormattedStringFrom(text:String) -> String
{
var resultString = ""
if text.characters.count > 0 && pattern.characters.count > 0
{
var finalText = ""
var stop = false
let tempString = prepareString(text)
var formatIndex = pattern.startIndex
var tempIndex = tempString.startIndex
while !stop
{
let formattingPatternRange = formatIndex ..< formatIndex.advancedBy(1)
if pattern.substringWithRange(formattingPatternRange) != String(replecementChar) {
finalText = finalText.stringByAppendingString(pattern.substringWithRange(formattingPatternRange))
}
else if tempString.characters.count > 0 {
let pureStringRange = tempIndex ..< tempIndex.advancedBy(1)
finalText = finalText.stringByAppendingString(tempString.substringWithRange(pureStringRange))
tempIndex = tempIndex.advancedBy(1)
}
formatIndex = formatIndex.advancedBy(1)
if formatIndex >= pattern.endIndex || tempIndex >= tempString.endIndex {
stop = true
}
resultString = finalText
}
}
return resultString
}
}
The follow link send to the complete source code:
https://gist.github.com/dedeexe/d9a43894081317e7c418b96d1d081b25
This solution was base on this article:
http://vojtastavik.com/2015/03/29/real-time-formatting-in-uitextfield-swift-basics/
There is a simple solution I learned with "We <3 Swift" if you can't either import Foundation, use round() and/or does not want a String:
var number = 31.726354765
var intNumber = Int(number * 1000.0)
var roundedNumber = Double(intNumber) / 1000.0
result: 31.726
Use this following code:
let intVal=56
let floatval:Double=56.897898
let doubleValue=89.0
let explicitDaouble:Double=89.56
let stringValue:"Hello"
let stringValue="String:\(stringValue) Integer:\(intVal) Float:\(floatval) Double:\(doubleValue) ExplicitDouble:\(explicitDaouble) "
The beauty of String(format:) is that you can save a formatting string and then reuse it later in dozen of places. It also can be localized in this single place. Where as in case of the interpolation approach you must write it again and again.
Simple functionality is not included in Swift, expected because it's included in other languages, can often be quickly coded for reuse. Pro tip for programmers to create a bag of tricks file that contains all this reuse code.
So from my bag of tricks we first need string multiplication for use in indentation.
#inlinable func * (string: String, scalar: Int) -> String {
let array = [String](repeating: string, count: scalar)
return array.joined(separator: "")
}
and then the code to add commas.
extension Int {
#inlinable var withCommas:String {
var i = self
var retValue:[String] = []
while i >= 1000 {
retValue.append(String(format:"%03d",i%1000))
i /= 1000
}
retValue.append("\(i)")
return retValue.reversed().joined(separator: ",")
}
#inlinable func withCommas(_ count:Int = 0) -> String {
let retValue = self.withCommas
let indentation = count - retValue.count
let indent:String = indentation >= 0 ? " " * indentation : ""
return indent + retValue
}
}
I just wrote this last function so I could get the columns to line up.
The #inlinable is great because it takes small functions and reduces their functionality so they run faster.
You can use either the variable version or, to get a fixed column, use the function version. Lengths set less than the needed columns will just expand the field.
Now you have something that is pure Swift and does not rely on some old objective C routine for NSString.
Since String(format: "%s" ...) is crashing at run time, here is code to allow write something like "hello".center(42); "world".alignLeft(42):
extension String {
// note: symbol names match to nim std/strutils lib:
func align (_ boxsz: UInt) -> String {
self.withCString { String(format: "%\(boxsz)s", $0) }
}
func alignLeft (_ boxsz: UInt) -> String {
self.withCString { String(format: "%-\(boxsz)s", $0) }
}
func center (_ boxsz: UInt) -> String {
let n = self.count
guard boxsz > n else { return self }
let padding = boxsz - UInt(n)
let R = padding / 2
guard R > 0 else { return " " + self }
let L = (padding%2 == 0) ? R : (R+1)
return " ".withCString { String(format: "%\(L)s\(self)%\(R)s", $0,$0) }
}
}
Success to try it:
var letters:NSString = "abcdefghijkl"
var strRendom = NSMutableString.stringWithCapacity(strlength)
for var i=0; i<strlength; i++ {
let rndString = Int(arc4random() % 12)
//let strlk = NSString(format: <#NSString#>, <#CVarArg[]#>)
let strlk = NSString(format: "%c", letters.characterAtIndex(rndString))
strRendom.appendString(String(strlk))
}