The string value varies sometimes it's
93.93% - 94.13, 85.34, %74.90, 88.21%
I just need to extract the double value like this.
93.93, 85.34, 74.90, 88.21
You can use regex to extract numbers from your string like this:
let sourceString = "93.93% - 94.13, 85.34, %74.90, 88.21%"
func getNumbers(from string : String) -> [String] {
let pattern = "((\\+|-)?([0-9]+)(\\.[0-9]+)?)|((\\+|-)?\\.?[0-9]+)" // Change this according to your requirement
let regex = try! NSRegularExpression(pattern: pattern)
let matches = regex.matches(in: string, range: NSRange(string.startIndex..., in: string))
let result = matches.map { (match) -> String in
let range = Range(match.range, in: string)!
return String(string[range])
}
return result
}
let numberArray = getNumbers(from: sourceString)
print(numberArray)
Result:
["93.93", "94.13", "85.34", "74.90", "88.21"]
you should try using a regex like this for example :
[0-9]{2}.[0-9]{2}
This regex find all string that match two numbers, then a dot and two numbers again.
for each value such as var str='%74.90'; use this line -
var double=str.match(/[+-]?\d+(\.\d+)?/g).map(function(v) { return parseFloat(v); })[0];
Use Scanner to scan the values. Scanner is highly configurable and designed for scanning string and numeric values from loosely demarcated strings. Below is the example:
let characterSet = CharacterSet.init(charactersIn: "0123456789.").inverted
let scanner = Scanner(string: "93.93% - 94.13, 85.34, %74.90, 88.21%")
scanner.charactersToBeSkipped = characterSet
var numStr: NSString?
while scanner.scanUpToCharacters(from: characterSet, into: &numStr) {
print(numStr ?? "")
}
Output:
93.93
94.13
85.34
74.90
88.21
It is easier to understand comparatively regex.
Related
First let me point out... I want to split a String or Substring with any character that is not an alphabet, a number, # or #. That means, I want to split with whitespaces(spaces & line breaks) and special characters or symbols excluding # and #
In Android Java, I am able to achieve this with:
String[] textArr = text.split("[^\\w_##]");
Now, I want to do the same in Swift. I added an extension to String and Substring classes
extension String {}
extension Substring {}
In both extensions, I added a method that returns an array of Substring
func splitWithRegex(by regexStr: String) -> [Substring] {
//let string = self (for String extension) | String(self) (for Substring extension)
let regex = try! NSRegularExpression(pattern: regexStr)
let range = NSRange(string.startIndex..., in: string)
return regex.matches(in: string, options: .anchored, range: range)
.map { match -> Substring in
let range = Range(match.range(at: 1), in: string)!
return string[range]
}
}
And when I tried to use it, (Only tested with a Substring, but I also think String will give me the same result)
let textArray = substring.splitWithRegex(by: "[^\\w_##]")
print("substring: \(substring)")
print("textArray: \(textArray)")
This is the out put:
substring: This,is a #random #text written for debugging
textArray: []
Please can Someone help me. I don't know if the problem if from my regex [^\\w_##] or from splitWithRegex method
The main reason why the code doesn't work is range(at: 1) which returns the content of the first captured group, but the pattern does not capture anything.
With just range the regex returns the ranges of the found matches, but I suppose you want the characters between.
To accomplish that you need a dynamic index starting at the first character. In the map closure return the string from the current index to the lowerBound of the found range and set the index to its upperBound. Finally you have to add manually the string from the upperBound of the last match to the end.
The Substring type is a helper type for slicing strings. It should not be used beyond a temporary scope.
extension String {
func splitWithRegex(by regexStr: String) -> [String] {
guard let regex = try? NSRegularExpression(pattern: regexStr) else { return [] }
let range = NSRange(startIndex..., in: self)
var index = startIndex
var array = regex.matches(in: self, range: range)
.map { match -> String in
let range = Range(match.range, in: self)!
let result = self[index..<range.lowerBound]
index = range.upperBound
return String(result)
}
array.append(String(self[index...]))
return array
}
}
let text = "This,is a #random #text written for debugging"
let textArray = text.splitWithRegex(by: "[^\\w_##]")
print(textArray) // ["This", "is", "a", "#random", "#text", "written", "for", "debugging"]
However in macOS 13 and iOS 16 there is a new API quite similar to the java API
let text = "This,is a #random #text written for debugging"
let textArray = Array(text.split(separator: /[^\w_##]/))
print(textArray)
The forward slashes indicate a regex literal
I am struggling to modify captured value with regex.
For example, I wanna change "Hello, he is hero" to "HEllo, HE is HEro" using Regex.
I know there are ways to change this without regex, but it is just an example to show the problem. I actually use the regex instead of just he, but I cannot provide it here. That is why using regex is required.
The code below somehow does not work. Are there any ways to make it work?
"Hello, he is hero".replacingOccurrences(
of: #"(he)"#,
with: "$1".uppercased(), // <- uppercased is not applied
options: .regularExpression
)
You need to use your regex in combination with Range (range(of:)) to find matches and then replace each found range separately
Here is a function as an extension to String that does this by using range(of:) starting from the start of the string and then moving the start index to match from forward to after the last match. The actual replacement is done inside a separate function that is passed as an argument
extension String {
func replace(regex: String, with replace: (Substring) -> String) -> String {
var string = self
var startIndex = self.startIndex
let endIndex = self.endIndex
while let range = string.range(of: regex, options: [.regularExpression] , range: startIndex..<endIndex) {
if range.isEmpty {
startIndex = string.index(startIndex, offsetBy: 1)
if startIndex >= endIndex { break }
continue
}
string.replaceSubrange(range, with: replace(string[range]))
startIndex = range.upperBound
}
return string
}
}
Example where we do an case insensitive search for words starting with "he" and replace each match with the uppercased version
let result = "Hello, he is hero. There he is".replace(regex: #"(?i)\bhe"#) {
$0.uppercased()
}
Output
HEllo, HE is HEro. There HE is
You can try NSRegularExpression. Something like:
import Foundation
var sourceStr = "Hello, he is hero"
let regex = try! NSRegularExpression(pattern: "(he)")
let matches = regex.matches(in: sourceStr, range: NSRange(sourceStr.startIndex..., in: sourceStr))
regex.enumerateMatches(in: sourceStr, range: NSRange(sourceStr.startIndex..., in: sourceStr)) { (match, _, _) in
guard let match = match else { return }
guard let range = Range(match.range, in: sourceStr) else { return }
let sub = sourceStr[range]
sourceStr = sourceStr.replacingOccurrences(of: sub, with: sub.uppercased(), options: [], range: range)
}
print(sourceStr)
this is the solution i can provide
var string = "Hello, he is hero"
let occurrence = "he"
string = string.lowercased().replacingOccurrences(
of: occurrence,
with: occurrence.uppercased(),
options: .regularExpression
)
print(string)
I am given a string like 4eysg22yl3kk and my output should be like this:
foureysgtweny-twoylthreekk or if I am given 0123 it should be output as one hundred twenty-three. So basically, as I scan the string, I need to convert numbers to string.
I do not know how to implement this in Swift as I iterate through the string? Any idea?
You actually have two basic problems.
The first is convert a "number" to "spelt out" value (ie 1 to one). This is actually easy to solve, as NumberFormatter has a spellOut style property
let formatter = NumberFormatter()
formatter.numberStyle = .spellOut
let text = formatter.string(from: NSNumber(value: 1))
which will result in "one", neat.
The other issue though, is how to you separate the numbers from the text?
While I can find any number of solutions for "extract" numbers or characters from a mixed String, I can't find one which return both, split on their boundaries, so, based on your input, we'd end up with ["4", "eysg", "22", "yl", "3", "kk"].
So, time to role our own...
func breakApart(_ text: String, withPattern pattern: String) throws -> [String]? {
do {
let regex = try NSRegularExpression(pattern: "[0-9]+", options: .caseInsensitive)
var previousRange: Range<String.Index>? = nil
var parts: [String] = []
for match in regex.matches(in: text, options: [], range: NSRange(location: 0, length: text.count)) {
guard let range = Range(match.range, in: text) else {
return nil
}
let part = text[range]
if let previousRange = previousRange {
let textRange = Range<String.Index>(uncheckedBounds: (lower: previousRange.upperBound, upper: range.lowerBound))
parts.append(String(text[textRange]))
}
parts.append(String(part))
previousRange = range
}
if let range = previousRange, range.upperBound != text.endIndex {
let textRange = Range<String.Index>(uncheckedBounds: (lower: range.upperBound, upper: text.endIndex))
parts.append(String(text[textRange]))
}
return parts
} catch {
}
return nil
}
Okay, so this is a little "dirty" (IMHO), but I can't seem to think of a better approach, hopefully someone will be kind enough to provide some hints towards one ;)
Basically what it does is uses a regular expression to find all the groups of numbers, it then builds an array, cutting the string apart around the matching boundaries - like I said, it's crude, but it gets the job done.
From there, we just need to map the results, spelling out the numbers as we go...
let formatter = NumberFormatter()
formatter.numberStyle = .spellOut
let value = "4eysg22yl3kk"
if let parts = try breakApart(value, withPattern: pattern) {
let result = parts.map { (part) -> String in
if let number = Int(part), let text = formatter.string(from: NSNumber(value: number)) {
return text
}
return part
}.joined(separator: " ")
print(result)
}
This will end up printing four eysg twenty-two yl three kk, if you don't want the spaces, just get rid of separator in the join function
I did this in Playgrounds, so it probably needs some cleaning up
I was able to solve my question without dealing with anything extra than converting my String to an array and check char by char. If I found a digit I was saving it in a temp String and as soon as I found out the next char is not digit, I converted my digit to its text.
let inputString = Array(string.lowercased())
I'm trying to create an internal function for the String class to get only AlphaNumeric characters and return a string. I'm running into a few errors with how to convert the matches back into a string using Regex. Can someone tell me how to fix the code or if there's an easier way?
I want something like this
let testString = "_<$abc$>_"
let alphaNumericString = testString.alphaNumeric() //abc
So far I have:
extension String {
internal func alphaNumeric() -> String {
let regex = try? NSRegularExpression(pattern: "[^a-z0-9]", options: .caseInsensitive)
let string = self as NSString
let results = regex?.matches(in: self, options: [], range: NSRange(location: 0, length: string.length))
let matches = results.map {
String(self[Range($0.range, in: self)!])
}
return matches.join()
}
}
You may directly use replacingOccurrences (that removes all non-overlapping matches from the input string) with [^A-Za-z0-9]+ pattern:
let str = "_<$abc$>_"
let pattern = "[^A-Za-z0-9]+"
let result = str.replacingOccurrences(of: pattern, with: "", options: [.regularExpression])
print(result) // => abc
The [^A-Za-z0-9]+ pattern is a negated character class that matches any char but the ones defined in the class, one or more occurrences (due to + quantifier).
See the regex demo.
Try below extension:
extension String {
var alphanumeric: String {
return self.components(separatedBy: CharacterSet.alphanumerics.inverted).joined().lowercased()
}
}
Usage: print("alphanumeric :", "_<$abc$>_".alphanumeric)
Output : abc
You can also use characterset for this like
extension String {
var alphaNumeric: String {
components(separatedBy: CharacterSet.alphanumerics.inverted).joined()
}
}
how can I substring the next 2 characters of a string after a certian character. For example I have a strings str1 = "12:34" and other like str2 = "12:345. I want to get the next 2 characters after : the colons.
I want a same code that will work for str1 and str2.
Swift's substring is complicated:
let str = "12:345"
if let range = str.range(of: ":") {
let startIndex = str.index(range.lowerBound, offsetBy: 1)
let endIndex = str.index(startIndex, offsetBy: 2)
print(str[startIndex..<endIndex])
}
It is very easy to use str.index() method as shown in #MikeHenderson's answer, but an alternative to that, without using that method is iterating through the string's characters and creating a new string for holding the first two characters after the ":", like so:
var string1="12:458676"
var nr=0
var newString=""
for c in string1.characters{
if nr>0{
newString+=String(c)
nr-=1
}
if c==":" {nr=2}
}
print(newString) // prints 45
Hope this helps!
A possible solution is Regular Expression,
The pattern checks for a colon followed by two digits and captures the two digits:
let string = "12:34"
let pattern = ":(\\d{2})"
let regex = try! NSRegularExpression(pattern: pattern, options: [])
if let match = regex.firstMatch(in: string, range: NSRange(location: 0, length: string.characters.count)) {
print((string as NSString).substring(with: match.rangeAt(1)))
}