I have a task to do something with a chess board. The input gives us a starting position of some chess figure. For example "b4" or "a6" or something like that. How can i decompose the input and make from it two integer numbers, like in C++:
string input;
cin>>input
int coord_x = input[0] - 'a';
int coord_y = input[1]
I cannot manage to do that in swift. I do something like:
let input : String=readLine()!
let characters = Array(input)
and then try to take the int but it doesnt work, no matter what i try...
and what type is the content of the Array in swift?
You can retrieve the c string representation like this:
let string = "a5"
let scalars = string.lowercased().cString(using: .ascii)!
let first = scalars[0]
let second = scalars[1]
It could be safer to retrieve the unicodeScalar characters instead:
let string = "a5".lowercased()
let characters = Array(string.unicodeScalars)
let first = characters[0].value - UnicodeScalar(unicodeScalarLiteral: "a").value
Related
I have this app of mine that reads datamatrix barcodes from drugs using the camera.
When it does for a particular drug, I receive this string from the detector, as seen on Xcode console:
0100000000D272671721123110700XXXX\U0000001d91D1
my problem is that \U0000001d91D1 part.
This code can be decomposed on the following:
01 00000000D27267 17 211231 10 700XXXX \U0000001d 91D1"
01 = drug code
17 = expiring date DMY
10 = batch number
The last part is the dosage rate
Now on another part of the application I am on the simulator, with no camera, so I need to pass this string to the module that decomposes the code.
I have tried to store the code as a string using
let code = "0100000000D272671721123110700XXXX\U0000001d91D1"
it complains about the inverted bar, so I change it to double bar
let code = "0100000000D272671721123110700XXXX\\U0000001d91D1"
the detector analyzes this string and concludes that the batch number is 700XXXX\U0000001d91D1, instead of just 700XXXX, so the information contained from the \ forward is lost.
I think this is unicode or something.
How do I create this string correctly.
You can use string transform to decode your hex unicode characters:
let str1 = #"0100000000D272671721123110700XXXX\U00000DF491D1"#
let str2 = #"0100000000D272671721123110700XXXX\U0000001d91D1"#
let decoded1 = str1.applyingTransform(.init("Hex-Any"), reverse: false)! // "0100000000D272671721123110700XXXX෴91D1"
let decoded2 = str2.applyingTransform(.init("Hex-Any"), reverse: false)! // "0100000000D272671721123110700XXXX91D1"
You can also get rid of the verbosity extending StringTransform and StringProtocol:
extension StringTransform {
static let hexToAny: Self = .init("Hex-Any")
static let anyToHex: Self = .init("Any-Hex")
}
extension StringProtocol {
var decodingHex: String {
applyingTransform(.hexToAny, reverse: false)!
}
var encodingHex: String {
applyingTransform(.anyToHex, reverse: false)!
}
}
Usage:
let str1 = #"0100000000D272671721123110700XXXX\U00000DF491D1"#
let str2 = #"0100000000D272671721123110700XXXX\U0000001d91D1"#
let decoded1 = str1.decodingHex // "0100000000D272671721123110700XXXX෴91D1"
let decoded2 = str2.decodingHex // "0100000000D272671721123110700XXXX91D1"
The \U0000001d substring probably represents code point U+001D INFORMATION SEPARATOR THREE, which is also the ASCII code point GS (group separator).
In a Swift string literal, we can write that code point using a Unicode escape sequence: \u{1d}. Try writing your string literal like this:
let code = "0100000000D272671721123110700XXXX\u{1d}91D1"
I have two String Type values as Int number.
I like to randomize between these two.
With this code:
let random = Int.random(in: myvar1...myvar2)
it does not work. How can i fix it?
I assume your variables look like this?
let myvar1: String = "1"
let myvar2: String = "10"
Those are both Strings, so myvar1...myvar2 becomes a range of String.
However, the random(in:) method takes in a range of Int, so you'll first need to convert them to Ints.
if let myvar1Int = Int(myvar1), let myvar2Int = Int(myvar2) {
let random = Int.random(in: myvar1Int...myvar2Int)
print(random) /// Result: 6
}
I have some Strings that vary in length but always end in "listing(number)"
myString = 9AMnep8MAziUCK7VwKF51mXZ2listing28
.
I want to get the String without "listing(number)":
9AMnep8MAziUCK7VwKF51mXZ2
.
Methods I've tried such as .index(of: ) only let you format based off one character. Any simple solutions?
A possible solution is to search for the substring with Regular Expression and remove the result (replace it with empty string)
let myString = "9AMnep8MAziUCK7VwKF51mXZ2listing28"
let trimmedString = myString.replacingOccurrences(of: "listing\\d+$", with: "", options: .regularExpression)
\\d+ searches for one ore more digits
$ represents the end of the string
Alternatively without creating a new string
var myString = "9AMnep8MAziUCK7VwKF51mXZ2listing28"
if let range = myString.range(of: "listing\\d+$", options: .regularExpression) {
myString.removeSubrange(range)
}
Another option is to split the string in parts with "listing" as separator
let result = myString.components(separatedBy: "listing").first
So to solve your issue find the code below with few comments written to try and explain each steps have taken. kindly note i have modified or arrived at this solution using this links as a guide.
https://stackoverflow.com/a/40070835/6596443
https://www.dotnetperls.com/substring-swift
extension String {
//
// Paramter inputString: This is the string you want to manipulate
// Paramter- startStringOfUnwanted: This is the string you want to start the removal or replacement from
//return : The expected output you want but can be emptystring if unable to
static func trimUnWantedEndingString(inputString: String,startStringOfUnwanted: String) -> String{
//Output string
var outputString: String?
//Getting the range based on the string content
if let range = myString.range(of: startStringOfUnwanted) {
//Get the lowerbound of the range
let lower = range.lowerBound
//Get the upperbound of the range
let upper = range.upperBound
//Get the integer position of the start index of the unwanted string i added plus one to ensure it starts from the right position
let startPos = Int(myString.distance(from: myString.startIndex, to: lower))+1
//Get the integer position of the end index of the unwanted string i added plus one to ensure it starts from the right position
let endPos = Int(myString.distance(from: myString.startIndex, to: upper))+1
//Substract the start int from the end int to get the integer value that will be used to get the last string i want to stop trimming at
let endOffsetBy = endPos-startPos
//get thes string char ranges of values
let result = myString.index(myString.startIndex, offsetBy: 0)..<myString.index(myString.endIndex, offsetBy: -endOffsetBy)
//converts the results to string or get the string representation of the result and then assign it to the OutputString
outputString = String(myString[result]);
}
return outputString ?? "";
}
}
let myString = "9AMnep8MAziUCK7VwKF51mXZ2listing28"
String.trimUnWantedEndingString(inputString: myString, startStringOfUnwanted:"listing")
Using Swift, I'm trying to take a list of numbers input in a text view in an app and create a sum of this list by extracting each number for a grade calculator. Also the amount of values put in by the user changes each time. An example is shown below:
String of: 98,99,97,96...
Trying to get: 98+99+97+96...
Please Help!
Thanks
Use components(separatedBy:) to break up the comma-separated string.
Use trimmingCharacters(in:) to remove spaces before and after each element
Use Int() to convert each element into an integer.
Use compactMap (previously called flatMap) to remove any items that couldn't be converted to Int.
Use reduce to sum up the array of Int.
let input = " 98 ,99 , 97, 96 "
let values = input.components(separatedBy: ",").compactMap { Int($0.trimmingCharacters(in: .whitespaces)) }
let sum = values.reduce(0, +)
print(sum) // 390
For Swift 3 and Swift 4.
Simple way: Hard coded. Only useful if you know the exact amount of integers coming up, wanting to get calculated and printed/used further on.
let string98: String = "98"
let string99: String = "99"
let string100: String = "100"
let string101: String = "101"
let int98: Int = Int(string98)!
let int99: Int = Int(string99)!
let int100: Int = Int(string100)!
let int101: Int = Int(string101)!
// optional chaining (if or guard) instead of "!" recommended. therefore option b is better
let finalInt: Int = int98 + int99 + int100 + int101
print(finalInt) // prints Optional(398) (optional)
Fancy way as a function: Generic way. Here you can put as many strings in as you need in the end. You could, for example, gather all the strings first and then use the array to have them calculated.
func getCalculatedIntegerFrom(strings: [String]) -> Int {
var result = Int()
for element in strings {
guard let int = Int(element) else {
break // or return nil
// break instead of return, returns Integer of all
// the values it was able to turn into Integer
// so even if there is a String f.e. "123S", it would
// still return an Integer instead of nil
// if you want to use return, you have to set "-> Int?" as optional
}
result = result + int
}
return result
}
let arrayOfStrings = ["98", "99", "100", "101"]
let result = getCalculatedIntegerFrom(strings: arrayOfStrings)
print(result) // prints 398 (non-optional)
let myString = "556"
let myInt = Int(myString)
How do you convert a String to UInt8 array?
var str = "test"
var ar : [UInt8]
ar = str
Lots of different ways, depending on how you want to handle non-ASCII characters.
But the simplest code would be to use the utf8 view:
let string = "hello"
let array: [UInt8] = Array(string.utf8)
Note, this will result in multi-byte characters being represented as multiple entries in the array, i.e.:
let string = "é"
print(Array(string.utf8))
prints out [195, 169]
There’s also .nulTerminatedUTF8, which does the same thing, but then adds a nul-character to the end if your plan is to pass this somewhere as a C string (though if you’re doing that, you can probably also use .withCString or just use the implicit conversion for bridged C functions.
let str = "test"
let byteArray = [UInt8](str.utf8)
swift 4
func stringToUInt8Array(){
let str:String = "Swift 4"
let strToUInt8:[UInt8] = [UInt8](str.utf8)
print(strToUInt8)
}
I came to this question looking for how to convert to a Int8 array. This is how I'm doing it, but surely there's a less loopy way:
Method on an Extension for String
public func int8Array() -> [Int8] {
var retVal : [Int8] = []
for thing in self.utf16 {
retVal.append(Int8(thing))
}
return retVal
}
Note: storing a UTF-16 encoded character (2 bytes) in an Int8 (1 byte) will lead to information loss.