I was trying to recreate Python's input() statement in Swift, I have seen some examples, but I am trying to make it better, firstly, my version removes the \n part of the string, also, I was trying to make it firstly print a prompt, so that var example = input() would just wait for the message, (which it does), but then var example = input("Enter text: ") would print Enter text: and wait for text to be inputed.
The problem is, swift seems to be messing up the print's order. For example, being the code:
import Foundation
func input(inputStatement: String? = nil) -> String {
if let inputStatement = inputStatement {
print(inputStatement, terminator:"")
}
let keyboard = NSFileHandle.fileHandleWithStandardInput()
let inputData = keyboard.availableData
var strData = NSString(data: inputData, encoding: NSUTF8StringEncoding) as! String
strData = strData.stringByReplacingOccurrencesOfString("\n", withString: "")
print()
return strData
}
print("Creating the input statement in Swift!")
var test = input("What's your name: ")
print("You entered: \(test).")
And the input text, "hi", this prints:
Creating the input statement in Swift!
hi
What's your name: You entered: hi.
And what I expected was:
Creating the input statement in Swift!
What's your name: hi
You entered: hi.
What am I missing here?
Thanks
The problem is that the standard output file descriptor is line buffered
when writing to a terminal (and fully buffered otherwise).
Therefore the output of
print(inputStatement, terminator:"")
is buffered and not written before the
print()
writes a newline. You can fix that by flushing the file
descriptor explicitly:
if let inputStatement = inputStatement {
print(inputStatement, terminator:"")
fflush(stdout)
}
Note also that there is a
public func readLine(stripNewline stripNewline: Bool = default) -> String?
which reads a line from standard input, with the option to
remove the trailing newline character. This function also
flushes standard output. Therefore a simpler implementation would be
func input(prompt: String = "") -> String {
print(prompt, terminator: "")
guard let reply = readLine(stripNewline: true) else {
fatalError("Unexpected EOF on input")
}
return reply
}
(Of course you might choose to handle "end of file" differently.)
Related
I know how to remove first character from a word in swift like this:
var data = "CITY Singapore"
data.removeFirst()
print(data)//ITY Singapore
what i want is to remove the first word and space so the result is "Singapore".
How can i remove the first word and leading space in swift?
You can try
let data = "CITY Singapore"
let res = data.components(separatedBy: " ").dropFirst().joined(separator: " ")
print(res)
Or
let res = data[data.range(of: " ")!.upperBound...] // may crash for no " " inside the string
Or you can go with this too
let strData = "CITY Singapore"
if let data = strData.components(separatedBy: " ").dropFirst().first {
// do with data
}
else {
// fallback
}
This is a Regular Expression solution, the benefit is to modify the string in place.
The pattern searches from the beginning of the string to the first space character
var data = "CITY Singapore"
if let range = data.range(of: "^\\S+\\s", options: .regularExpression) {
data.removeSubrange(range)
}
You can use String's enumerateSubstrings in range method (Foundation) using byWords option and remove the first enclosing range. You need also to stop enumeration after removing the range at the first occurrence:
var string = "CITY Singapore"
string.enumerateSubstrings(in: string.startIndex..., options: .byWords) { (_, _, enclosingRange, stop) in
string.removeSubrange(enclosingRange)
stop = true
}
string // "Singapore"
The input to dictionary(fromTXTRecord:) comes from the network, potentially from outside the app, or even the device. However, Apple's docs say:
... Fails an assertion if txtData cannot be represented as an NSDictionary object.
Failing an assertion leaves the programmer (me) with no way of handling the error, which seems illogic for a method that processes external data.
If I run this in Terminal on a Mac:
dns-sd -R 'My Service Name' _myservice._tcp local 4567 asdf asdf
my app, running in an iPhone, crashes.
dictionary(fromTXTRecord:) expects the TXT record data (asdf asdf) to be in key=val form. If, like above, a word doesn't contain any = the method won't be able to parse it and fail the assertion.
I see no way of solving this problem other than not using that method at all and implementing my own parsing, which feels wrong.
Am I missing something?
Here's a solution in Swift 4.2, assuming the TXT record has only strings:
/// Decode the TXT record as a string dictionary, or [:] if the data is malformed
public func dictionary(fromTXTRecord txtData: Data) -> [String: String] {
var result = [String: String]()
var data = txtData
while !data.isEmpty {
// The first byte of each record is its length, so prefix that much data
let recordLength = Int(data.removeFirst())
guard data.count >= recordLength else { return [:] }
let recordData = data[..<(data.startIndex + recordLength)]
data = data.dropFirst(recordLength)
guard let record = String(bytes: recordData, encoding: .utf8) else { return [:] }
// The format of the entry is "key=value"
// (According to the reference implementation, = is optional if there is no value,
// and any equals signs after the first are part of the value.)
// `ommittingEmptySubsequences` is necessary otherwise an empty string will crash the next line
let keyValue = record.split(separator: "=", maxSplits: 1, omittingEmptySubsequences: false)
let key = String(keyValue[0])
// If there's no value, make the value the empty string
switch keyValue.count {
case 1:
result[key] = ""
case 2:
result[key] = String(keyValue[1])
default:
fatalError()
}
}
return result
}
I'm still hoping there's something I'm missing here, but in the mean time, I ended up checking the data for correctness and only then calling Apple's own method.
Here's my workaround:
func dictionaryFromTXTRecordData(data: NSData) -> [String:NSData] {
let buffer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(data.bytes), count: data.length)
var pos = 0
while pos < buffer.count {
let len = Int(buffer[pos])
if len > (buffer.count - pos + 1) {
return [:]
}
let subdata = data.subdataWithRange(NSRange(location: pos + 1, length: len))
guard let substring = String(data: subdata, encoding: NSUTF8StringEncoding) else {
return [:]
}
if !substring.containsString("=") {
return [:]
}
pos = pos + len + 1
}
return NSNetService.dictionaryFromTXTRecordData(data)
}
I'm using Swift 2 here. All contributions are welcome. Swift 3 versions, Objective-C versions, improvements, corrections.
I just ran into this one using Swift 3. In my case the problem only occurred when I used NetService.dictionary(fromTXTRecord:) but did not occur when I switched to Objective-C and called NSNetService dictionaryFromTXTRecord:. When the Objective-C call encounters an entry without an equal sign it creates a key containing the data and shoves it into the dictionary with an NSNull value. From what I can tell the Swift version then enumerates that dictionary and throws a fit when it sees the NSNull. My solution was to add an Objective-C file and a utility function that calls dictionaryFromTXTRecord: and cleans up the results before handing them back to my Swift code.
I just want to see whether there is an established way to do this, or how one would go about this.
I have a text field that essentially acts as a form in my iOs app where a user can post something. I can't have users posting swear words/inappropriate crap, so I want to filter out and display an error if the string they enter contains one of these words.
How do other apps in Swift do this? Do they just search through the string to see if it contains the word (obviously not within other words, but standing alone) or is there another method?
How can I accurately filter out the swear words from my user post in Swift?
Construct a list of words you consider to be swear words, and simply check the user entered string whether any of these words are contained within the string.
Swift 3:
import Foundation
func containsSwearWord(text: String, swearWords: [String]) -> Bool {
return swearWords
.reduce(false) { $0 || text.contains($1.lowercased()) }
}
// example usage
let listOfSwearWords = ["darn", "crap", "newb"]
/* list as lower case */
let userEnteredText1 = "This darn didelo thread is a no no."
let userEnteredText2 = "This fine didelo thread is a go."
print(containsSwearWord(text: userEnteredText1, swearWords: listOfSwearWords)) // true
print(containsSwearWord(text: userEnteredText2, swearWords: listOfSwearWords)) // false
Swift 2.2:
import Foundation
func containsSwearWord(text: String, swearWords: [String]) -> Bool {
return swearWords
.reduce(false) { $0 || text.containsString($1.lowercaseString) }
}
// example usage
let listOfSwearWords = ["darn", "crap", "newb"]
/* list as lower case */
let userEnteredText1 = "This darn didelo thread is a no no."
let userEnteredText2 = "This fine didelo thread is a go."
print(containsSwearWord(userEnteredText1, swearWords: listOfSwearWords)) // true
print(containsSwearWord(userEnteredText2, swearWords: listOfSwearWords)) // false
I created a class that enables you to feed a string in and remove profanity. Here's a link to the repo.
Here's the code:
class ProfanityFilter: NSObject {
static let sharedInstance = ProfanityFilter()
private override init() {}
// Customize as needed
private let dirtyWords = "\\b(ducker|mother ducker|motherducker|shot|bad word|another bad word|)\\b"
// Courtesy of Martin R
// https://stackoverflow.com/users/1187415/martin-r
private func matches(for regex: String, in text: String) -> [String] {
do {
let regex = try NSRegularExpression(pattern: regex, options: [.caseInsensitive])
let nsString = text as NSString
let results = regex.matches(in: text, range: NSRange(location: 0, length: nsString.length))
return results.map { nsString.substring(with: $0.range)}
} catch let error {
print("invalid regex: \(error.localizedDescription)")
return []
}
}
public func cleanUp(_ string: String) -> String {
let dirtyWords = matches(for: self.dirtyWords, in: string)
if dirtyWords.count == 0 {
return string
} else {
var newString = string
dirtyWords.forEach({ dirtyWord in
let newWord = String(repeating: "😲", count: dirtyWord.characters.count)
newString = newString.replacingOccurrences(of: dirtyWord, with: newWord, options: [.caseInsensitive])
})
return newString
}
}
}
Usage:
yourLabel.text = ProfanityFilter.sharedInstance.cleanUp(yourString)
Extension checking for foul language.
Swift 4.2
Example Usage:
"poop".containsBadWord()
Extension:
extension String {
func containsBadWord()->Bool {
//Sorry for bad words
let badWords = ["insert","bad","words","here","poop"]
for word in badWords {
if lowercased().contains(word) {
return true
}
}
return false
}
}
I would suggest looking into an API to which you can submit a string and get a JSON response containing information such as:
Is the string bad?
Total # of bad words contained in string
An array containing all recognized bad words
A censored version of the input string
I found a couple sources via Google. Check these out and do a little more research to find if an API is the best fit for you and which one you should use. I would assume that using an API like the one I have listed below would be the most practical approach, as you would NOT have to compile a list of "bad" words yourself and use resources from the device to sort through the list (which can contain thousands of words).
Rather, you can simply submit a string using the API to get a network response containing the data in JSON format from the API server.
Why not let the API Server do the logic for you and just spit out an answer?
NeutrinoAPI
If this method returns a range,
str.range(of: "darn|crap|newb", options: [.regularExpressionSearch, .caseInsensitiveSearch], range: str.startIndex..<str.endIndex, locale:nil)
an offensive word has been found. While this method can be used to remove the offending strings:
str.replacingOccurrences(of: "darn|crap|newb", with: "", options: [.regularExpressionSearch, .caseInsensitiveSearch])
If you filter bad words locally you wouldn’t easily accommodate many languages, also as new bad words appear, you would have to waste a developers time manually putting in bad words, alternatively, there are apis designed for this purpose: https://www.moderatecontent.com/documentation/badwords
I'm getting JSON like this from the server:
{
"unicode":"1f468-1f468-1f467-1f467"
}
and I'm supposed to translate it into its composite character for display and/or copying to the pasteboard: 👨👨👧👧
The solution so far comes from this SO question:
let u = json["unicode"] as? String
let dashless = u.characters.split{$0 == "-"}.map(String.init)
let charArray = dashless.map { char -> Character in
let code = Int(strtoul(char, nil, 16))
return Character(UnicodeScalar(code))
}
let unicode = String(charArray)
UIPasteboard.generalPasteboard().string = unicode
This works great for single-character emoji definitions.
E.g., I can run the code above with this JSON…
{
"unicode":"1f4a9"
}
…and paste the expected result: 💩. But when I do with the mmgg family emoji listed earlier, I get the following in iOS, minus the spaces: 👨 👨 👧 👧. They just don't seem to want to combine when pasted into a text field.
Is this an iOS bug, or am I doing something wrong?
try this in your playground, to see the difference ...
"👨👨👧👧".unicodeScalars.forEach { (c) in
print(c.escape(asASCII: true),terminator: "")
}
print("")
"👨👨👧👧".unicodeScalars.forEach { (c) in
print(c.escape(asASCII: true), terminator: "")
}
/*
\u{0001F468}\u{0001F468}\u{0001F467}\u{0001F467}
\u{0001F468}\u{200D}\u{0001F468}\u{200D}\u{0001F467}\u{200D}\u{0001F467}
*/
your original, slightly modified code
import Darwin // stroul
let u = "1f468-1f468-1f467-1f467"
let dashless = u.characters.split{$0 == "-"}.map(String.init)
let emoji = dashless.map { char -> String in
let code = Int(strtoul(char, nil, 16))
return String(UnicodeScalar(code))
}.joinWithSeparator("\u{200D}")
print(emoji) // 👨👨👧👧
pure Swift code, no Foundation, without strtoul
let u = "1f468-1f468-1f467-1f467"
let emoji = u.characters.split("-")
.map {String(UnicodeScalar(Int(String($0),radix: 16) ?? 0))}
.joinWithSeparator("\u{200D}")
print(emoji) // 👨👨👧👧
for example I have a String text like : "I have to go to the kitchen"
and If I searched this text using the 'av' phrase I want a way that return me the whole word 'have'
how I can do this in swift
There is very nice solution with filter in swift.You can use rangeOfString method of String with filter to get only filtered string having "av"
var s = "I have to go to the kitchen"
//will return "have"
let abc:[String] = s.componentsSeparatedByString(" ").filter({ $0.rangeOfString("av", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil, locale: nil) != nil } )
There is an API for that, enumerateSubstrings(in:options:using:)
The byWords option returns all words in the closure
let string = "I have to go to the kitchen"
var found : String?
string.enumerateSubstrings(in: string.startIndex..., options: .byWords) { substring, _, _, stop in
if let word = substring, word.contains("av") {
found = word
stop = true
}
}
print(found ?? "not found")
Split your string into array by space char (" "), and return component that contains your 'av' string.
let words = stringYouWantToSearchIn.componentsSeparatedByString(" ")
for word in words
{
var range = word.rangeOfString(lastWord)
if (range != nil)
{
//you got what do you want in 'word variable'
break
}
}