I'm trying to create a function that validate my string if it is using this format
ABC123
First three characters should be letters and the other 3 should be numbers
I have no idea on how to start
Thanks
You can do it with a regular expression match on strings, like this:
let str = "ABC123"
let optRange = str.rangeOfString("^[A-Za-z]{3}\\d{3}$", options: .RegularExpressionSearch)
if let range = optRange {
println("Matched")
} else {
println("Not matched")
}
Regex above requires that the match occupied the whole string (the ^ and $ anchors at both ends), has three letters [A-Za-z]{3} and three digits \\d{3}.
You can also use it as an extension if you would like to:
extension String {
var match: Bool {
return rangeOfString("^[A-Za-z]{3}\\d{3}$", options: .RegularExpressionSearch) != nil
}
}
"ABC123".match // true
Related
Problem: i am currently trying to Sort a List in SwiftUI according to the Items First Character. I also would like to implement a Section for all Items, which doesn't begin with a Character of the Alphabet (Numbers, Special Chars).
My Code so far:
let nonAlphabetItems = items.filter { $0.name.uppercased() != /* beginns with A - Z */ }
Does anyone has a Solution for this Issue. Of course I could do a huge Loop Construct, however I hope there is a more elegant way.
Thanks for your help.
You can check if a string range "A"..."Z" contains the first letter of your name property:
struct Item {
let name: String
}
let items: [Item] = [.init(name: "Def"),.init(name: "Ghi"),.init(name: "123"),.init(name: "Abc")]
let nonAlphabetItems = items.filter { !("A"..."Z" ~= ($0.name.first?.uppercased() ?? "#")) }
nonAlphabetItems // [{name "123"}]
Expanding on this topic we can extend Character to add a isAsciiLetter property:
extension Character {
var isAsciiLetter: Bool { "A"..."Z" ~= self || "a"..."z" ~= self }
}
This would allow to extend StringProtocol to check is a string starts with an ascii letter:
extension StringProtocol {
var startsWithAsciiLetter: Bool { first?.isAsciiLetter == true }
}
And just a helper to negate a boolean property:
extension Bool {
var negated: Bool { !self }
}
Now we can filter the items collection as follow:
let nonAlphabetItems = items.filter(\.name.startsWithAsciiLetter.negated) // [{name "123"}]
If you need an occasional filter, you could simply write a condition combining standard predicates isLetter and isASCII which are already defined for Character. It's as simple as:
let items = [ "Abc", "01bc", "Ça va", "", " ", "𓀫𓀫𓀫𓀫"]
let nonAlphabetItems = items.filter { $0.isEmpty || !$0.first!.isASCII || !$0.first!.isLetter }
print (nonAlphabetItems) // -> Output: ["01bc", "Ça va", "", " ", "𓀫𓀫𓀫𓀫"]
If the string is not empty, it has for sure a first character $0.first!. It is tempting to use isLetter , but it appears to be true for many characters in many local alphabets, including for example the antique Egyptian hieroglyphs like "𓀫" or the French alphabet with "Ç"and accented characters. This is why you need to restrict it to ASCII letters, to limit yourself to the roman alphabet.
You can use NSCharacterSet in the following way :
let phrase = "Test case"
let range = phrase.rangeOfCharacter(from: characterSet)
// range will be nil if no letters is found
if let test = range {
println("letters found")
}
else {
println("letters not found")
}```
You can deal with ascii value
extension String {
var fisrtCharacterIsAlphabet: Bool {
guard let firstChar = self.first else { return false }
let unicode = String(firstChar).unicodeScalars
let ascii = Int(unicode[unicode.startIndex].value)
return (ascii >= 65 && ascii <= 90) || (ascii >= 97 && ascii <= 122)
}
}
var isAlphabet = "Hello".fisrtCharacterIsAlphabet
The Character type has a property for this:
let x: Character = "x"
x.isLetter // true for letters, false for punctuation, numbers, whitespace, ...
Note that this will include characters from other alphabets (Greek, Cyrillic, Chinese, ...).
As String is a Sequence with Element equal to Character, we can use the .first property to get the first char.
With this, you can filter your items:
let filtered = items.filter { $0.name.first?.isLetter ?? false }
You can get this done through this simple String extension
extension StringProtocol {
var isFirstCharacterAlp: Bool {
first?.isASCII == true && first?.isLetter == true
}
}
Usage:
print ("H1".isFirstCharacterAlp)
print ("ابراهيم1".isFirstCharacterAlp)
Output
true
false
Happy Coding!
Reference
I use this method for patterning the phone number in UITextField at the .editingChange event
But the delete key only removes the numbers
extension String{
func applyPatternOnNumbers(pattern: String) -> String {
let replacmentCharacter: Character = "#"
let pureNumber = self.replacingOccurrences( of: "[^۰-۹0-9]", with: "", options: .regularExpression)
var result = ""
var pureNumberIndex = pureNumber.startIndex
for patternCharacter in pattern {
if patternCharacter == replacmentCharacter {
guard pureNumberIndex < pureNumber.endIndex else { return result }
result.append(pureNumber[pureNumberIndex])
pureNumber.formIndex(after: &pureNumberIndex)
} else {
result.append(patternCharacter)
}
}
return result
}
}
use at the editingChange event
let pattern = "+# (###) ###-####"
let mobile = textField.text.substring(to: pattern.count-1)
textfield.text = mobile.applyPatternOnNumbers(pattern: pattern)
// print(textfield.text) +1 (800) 666-8888
the problem is space & - , ( , ) chars can not to be removed
The RegEx you are trying is to not consider digits only:
[^۰-۹0-9]
I'm not sure, but you may change it to:
[^۰-۹0-9\s-\(\)]
and it may work. You might just add a \ before your special chars inside [] and you can any other chars into it that you do not need to be replaced.
Or you may simplify it to
[^\d\s-\(\)]
and it might work.
Method 2
You may use this RegEx which is an exact match to the phone number format you are having:
\+\d+\s\(\d{3}\)\s\d{3}-\d{4}
You may remove the first +, if it is unnecessary
\d+\s\(\d{3}\)\s\d{3}-\d{4}
i was looking for an answer but haven't found one yet, so:
For example: i have a string like "#blablub" and i want to remove the # at the beginning, i can just simply remove the first char. But, if i have a string with "#####bla#blub" and i only want to remove all # only at the beginning of the first string, i have no idea how to solve that.
My goal is to get a string like this "bla#blub", otherwise it would be to easy with replaceOccourencies...
I hope you can help.
Swift2
func ltrim(str: String, _ chars: Set<Character>) -> String {
if let index = str.characters.indexOf({!chars.contains($0)}) {
return str[index..<str.endIndex]
} else {
return ""
}
}
Swift3
func ltrim(_ str: String, _ chars: Set<Character>) -> String {
if let index = str.characters.index(where: {!chars.contains($0)}) {
return str[index..<str.endIndex]
} else {
return ""
}
}
Usage:
ltrim("#####bla#blub", ["#"]) //->"bla#blub"
var str = "###abc"
while str.hasPrefix("#") {
str.remove(at: str.startIndex)
}
print(str)
I recently built an extension to String that will "clean" a string from the start, end, or both, and allow you to specify a set of characters which you'd like to get rid of. Note that this will not remove characters from the interior of the String, but it would be relatively straightforward to extend it to do that. (NB built using Swift 2)
enum stringPosition {
case start
case end
case all
}
func trimCharacters(charactersToTrim: Set<Character>, usingStringPosition: stringPosition) -> String {
// Trims any characters in the specified set from the start, end or both ends of the string
guard self != "" else { return self } // Nothing to do
var outputString : String = self
if usingStringPosition == .end || usingStringPosition == .all {
// Remove the characters from the end of the string
while outputString.characters.last != nil && charactersToTrim.contains(outputString.characters.last!) {
outputString.removeAtIndex(outputString.endIndex.advancedBy(-1))
}
}
if usingStringPosition == .start || usingStringPosition == .all {
// Remove the characters from the start of the string
while outputString.characters.first != nil && charactersToTrim.contains(outputString.characters.first!) {
outputString.removeAtIndex(outputString.startIndex)
}
}
return outputString
}
A regex-less solution would be:
func removePrecedingPoundSigns(s: String) -> String {
for (index, char) in s.characters.enumerate() {
if char != "#" {
return s.substringFromIndex(s.startIndex.advancedBy(index))
}
}
return ""
}
A swift 3 extension starting from OOPer's response:
extension String {
func leftTrim(_ chars: Set<Character>) -> String {
if let index = self.characters.index(where: {!chars.contains($0)}) {
return self[index..<self.endIndex]
} else {
return ""
}
}
}
As Martin R already pointed out in a comment above, a regular expression is appropriate here:
myString.replacingOccurrences(of: #"^#+"#, with: "", options: .regularExpression)
You can replace the inner # with any symbol you're looking for, or you can get more complicated if you're looking for one of several characters or a group etc. The ^ indicates it's the start of the string (so you don't get matches for # symbols in the middle of the string) and the + represents "1 or more of the preceding character". (* is 0 or more but there's not much point in using that here.)
Note the outer hash symbols are to turn the string into a raw String so escaping is not needed (though I suppose there's nothing that actually needs to be escaped in this particular example).
To play around with regex I recommend: https://regexr.com/
I have a string: "Hey #username that's funny". For a given string, how can I search the string to return all ranges of string with first character # and last character to get the username?
I suppose I can get all indexes of # and for each, get the substringToIndex of the next space character, but wondering if there's an easier way.
If your username can contain only letters and numbers, you can use regular expression for that:
let s = "Hey #username123 that's funny"
if let r = s.rangeOfString("#\\w+", options: NSStringCompareOptions.RegularExpressionSearch) {
let name = s.substringWithRange(r) // #username123"
}
#Vladimir's answer is correct, but if you're trying to find multiple occurrences of "username", this should also work:
let s = "Hey #username123 that's funny"
let ranges: [NSRange]
do {
// Create the regular expression.
let regex = try NSRegularExpression(pattern: "#\\w+", options: [])
// Use the regular expression to get an array of NSTextCheckingResult.
// Use map to extract the range from each result.
ranges = regex.matchesInString(s, options: [], range: NSMakeRange(0, s.characters.count)).map {$0.range}
}
catch {
// There was a problem creating the regular expression
ranges = []
}
for range in ranges {
print((s as NSString).substringWithRange(range))
}
I have several text fields used to enter full name and short name, among other data. My task is:
Check if entered full name matches the standard Russian Cyrillic full name pattern:
Иванов Иван Иванович (three capitalized Cyrillic strings separated by spaces)
If it matches, create another string by auto-contracting full name according to pattern below and enter it to the corresponding text field:
Иванов И.И. (first string, space, first character of the second string, dot, first character of the third string, dot)
If it doesn't match, do nothing.
Currently I use the following code:
let fullNameArray = fullNameField.text!.characters.split{$0 == " "}.map(String.init)
if fullNameArray.count == 3 {
if fullNameArray[0] == fullNameArray[0].capitalizedString && fullNameArray[1] == fullNameArray[1].capitalizedString && fullNameArray[2] == fullNameArray[2].capitalizedString {
shortNameField.text = "\(fullNameArray[0]) \(fullNameArray[1].characters.first!).\(fullNameArray[2].characters.first!)."
}
}
How can I improve it? Maybe regular expressions could help me? If so, could you post some sample code?
My current solution:
do {
let regex = try NSRegularExpression(pattern: "^\\p{Lu}\\p{Ll}+\\s\\p{Lu}\\p{Ll}+\\s\\p{Lu}\\p{Ll}+$", options: .AnchorsMatchLines)
if regex.firstMatchInString(fullNameField.text!, options: [], range: NSMakeRange(0, fullNameField.text!.characters.count)) != nil {
let fullNameArray = fullNameField.text!.characters.split(" ").map(String.init)
shortNameField.text = "\(fullNameArray[0]) \(fullNameArray[1].characters.first!).\(fullNameArray[2].characters.first!)."
}
else {
shortNameField.text = ""
}
} catch let error as NSError {
print(error.localizedDescription)
}
Processes my full name pattern correctly.