I have a string.
I have a word inside that string
I want to basically get rid of everything in the string and the word.
But everything after the word in the string I want to keep.
This word and string can be dynamic.
Here is what I got so far and I am finding it hard to find online resources to solve this.
Error:
Cannot convert value of type 'String' to expected argument type 'String.Element' (aka 'Character')
Here is my code
var bigString = "This is a big string containing the pattern"
let pattern = "containing" //random word that is inside big string
let indexEndOfPattern = bigString.lastIndex(of: pattern) // Error here
let newText = bigString[indexEndOfPattern...]
bigString = newText // bigString should now be " the pattern"
Think in ranges and bounds, lastIndex(of expects a single Character
var bigString = "This is a big string containing the pattern"
let pattern = "containing" //random word that is inside big string
if let rangeOfPattern = bigString.range(of: pattern) {
let newText = String(bigString[rangeOfPattern.upperBound...])
bigString = newText // bigString should now be " the pattern"
}
Related
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")
I am trying to replace every occurrence of a space with two random characters (out of 103). The problem is that it is always the same 2 characters every time, which makes sense if you look at the code
I'm pretty new to Swift and Xcode and I've already tried a bunch of things, like using a "for" loop.
newSentence = passedSentence.replacingOccurrences(of: " ", with: " \(randomArray[Int.random(in: 0...103)]) \(randomArray[Int.random(in: 0...103)]) ")
resultText.text = newSentence
As I said before, it is always the same 2 characters when I want it to "refresh" for every occurrence of a space.
Using map(_:) method instead of replacingOccurrences(of:with:) to get the desired result.
replacingOccurrences(of:with:)
A new string in which all occurrences of target in the receiver are
replaced by replacement.
It replaces all the occurrences with the same instance that is passed in the replacementString i.e. randomArray[Int.random(in: 0...103) (randomArray[Int.random(in: 0...103)] is executed only once and used throughout the string for all occurrences of " ".
let passedSentence = "This is a sample sentence"
let newSentence = (passedSentence.map { (char) -> String in
if char == " " {
return " \(randomArray[Int.random(in: 0...103)]) \(randomArray[Int.random(in: 0...103)]) "
}
return String(char)
}).joined()
print(newSentence)
In case the you're using the whole range of randomArray, i.e. if randomArray contains 104 elements i.e. 0...103, you can directly use randomElement() on randomArray instead of using random(in:) on Int, i.e.
Use
randomArray.randomElement()
instead of
randomArray[Int.random(in: 0...103)]
Yes, your behavior is expected given your code. The parameter passed in with: is only executed once so if it generates "SX", that will be used to replace ALL the occurrences of " "(space) in your passedSentence.
To get your expected behavior, you would have to loop:
var rangeOfEmptyString = passedSentence.range(of: " ")
while rangeOfEmptyString != nil {
let randomModifier = "\(randomArray[Int.random(in: 0...103)])\(randomArray[Int.random(in: 0...103)])"
passedSentence = passedSentence.replacingCharacters(in: rangeOfEmptyString!, with: randomModifier)
rangeOfEmptyString = passedSentence.range(of: " ")
}
You should replace each space with different random elements of the array. replacingOccurrences method replaces all ranges at once. Get the range of space one by one and replace with unique random elements
let randomArray:[String] = ["a","b","c","d"]
var passedSentence = "This is a long text"
var start = passedSentence.startIndex
while let range = passedSentence[start...].rangeOfCharacter(from: .whitespaces),
let random1 = randomArray.randomElement(),
let random2 = randomArray.randomElement() {
let replacementString = " \(random1) \(random2) "
passedSentence.replaceSubrange(range, with: " \(random1) \(random2) ")
start = passedSentence.index(range.upperBound, offsetBy: replacementString.count)
}
print(passedSentence)
To get the random element from an array don't use randomArray[Int.random(in: 0...103)]. You can use randomElement()
I would like to change the formatting of the first line of text in an NSTextView (give it a different font size and weight to make it look like a headline). Therefore, I need the range of the first line. One way to go is this:
guard let firstLineString = textView.string.components(separatedBy: .newlines).first else {
return
}
let range = NSRange(location: 0, length: firstLineString.count)
However, I might be working with quite long texts so it appears to be inefficient to first split the entire string into line components when all I need is the first line component. Thus, it seems to make sense to use the firstIndex(where:) method:
let firstNewLineIndex = textView.string.firstIndex { character -> Bool in
return CharacterSet.newlines.contains(character)
}
// Then: Create an NSRange from 0 up to firstNewLineIndex.
This doesn't work and I get an error:
Cannot convert value of type '(Unicode.Scalar) -> Bool' to expected argument type 'Character'
because the contains method accepts not a Character but a Unicode.Scalar as a parameter (which doesn't really make sense to me because then it should be called a UnicodeScalarSet and not a CharacterSet, but nevermind...).
My question is:
How can I implement this in an efficient way, without first slicing the whole string?
(It doesn't necessarily have to use the firstIndex(where:) method, but appears to be the way to go.)
A String.Index range for the first line in string can be obtained with
let range = string.lineRange(for: ..<string.startIndex)
If you need that as an NSRange then
let nsRange = NSRange(range, in: string)
does the trick.
You can use rangeOfCharacter, which returns the Range<String.Index> of the first character from a set in your string:
extension StringProtocol where Index == String.Index {
var partialRangeOfFirstLine: PartialRangeUpTo<String.Index> {
return ..<(rangeOfCharacter(from: .newlines)?.lowerBound ?? endIndex)
}
var rangeOfFirstLine: Range<Index> {
return startIndex..<partialRangeOfFirstLine.upperBound
}
var firstLine: SubSequence {
return self[partialRangeOfFirstLine]
}
}
You can use it like so:
var str = """
some string
with new lines
"""
var attributedString = NSMutableAttributedString(string: str)
let firstLine = NSAttributedString(string: String(str.firstLine))
// change firstLine as you wish
let range = NSRange(str.rangeOfFirstLine, in: str)
attributedString.replaceCharacters(in: range, with: firstLine)
var hello = "hello, how are you?"
var hello2 = "hello, how are you #tom?"
i want to delete every letter behind the # sign.
result should be
var hello2 = "hello, how are you #tom?"
->
hello2.trimmed()
print(hello2.trimmed())
-> "hello, how are you"
Update
As i want to use it to link multiple users and replace the space behind #sign with the correct name, I always need the reference to the latest occurrence of the #sign to replace it.
text3 = "hey i love you #Tom #Marcus #Peter"
Example what the final version should look like
to start off
var text = "hello #tom #mark #mathias"
i want to always get the index of the latest # sign in the text
Expanding on #appzYourLife answer, the following will also trim off the whitespace characters after removing everything after the # symbol.
import Foundation
var str = "hello, how are you #tom"
if str.contains("#") {
let endIndex = str.range(of: "#")!.lowerBound
str = str.substring(to: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
}
print(str) // Output - "hello, how are you"
UPDATE:
In response to finding the last occurance of the # symbol in the string and removing it, here is how I would approach it:
var str = "hello, how are you #tom #tim?"
if str.contains("#") {
//Reverse the string
var reversedStr = String(str.characters.reversed())
//Find the first (last) occurance of #
let endIndex = reversedStr.range(of: "#")!.upperBound
//Get the string up to and after the # symbol
let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
//Store the new string over the original
str = String(newStr.characters.reversed())
//str = "hello, how are you #tom"
}
Or looking at #appzYourLife answer use range(of:options:range:locale:) instead of literally reversing the characters
var str = "hello, how are you #tom #tim?"
if str.contains("#") {
//Find the last occurrence of #
let endIndex = str.range(of: "#", options: .backwards, range: nil, locale: nil)!.lowerBound
//Get the string up to and after the # symbol
let newStr = str.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
//Store the new string over the original
str = newStr
//str = "hello, how are you #tom"
}
As an added bonus, here is how I would approach removing every # starting with the last and working forward:
var str = "hello, how are you #tom and #tim?"
if str.contains("#") {
while str.contains("#") {
//Reverse the string
var reversedStr = String(str.characters.reversed())
//Find the first (last) occurance of #
let endIndex = reversedStr.range(of: "#")!.upperBound
//Get the string up to and after the # symbol
let newStr = reversedStr.substring(from: endIndex).trimmingCharacters(in: .whitespacesAndNewlines)
//Store the new string over the original
str = String(newStr.characters.reversed())
}
//after while loop, str = "hello, how are you"
}
let text = "hello, how are you #tom?"
let trimSpot = text.index(of: "#") ?? text.endIndex
let trimmed = text[..<trimSpot]
Since a string is a collection of Character type, it can be accessed as such. The second line finds the index of the # sign and assigns its value to trimSpot, but if it is not there, the endIndex of the string is assigned through the use of the nil coalescing operator
??
The string, or collection of Characters, can be provided a range that will tell it what characters to get. The expression inside of the brackets,
..<trimSpot
is a range from 0 to trimSpot-1. So,
text[..<trimSpot]
returns an instance of type Substring, which points at the original String instance.
You need to find the range of the "#" and then use it to create a substring up to the index before.
import Foundation
let text = "hello, how are you #tom?"
if let range = text.range(of: "#") {
let result = text.substring(to: range.lowerBound)
print(result) // "hello, how are you "
}
Considerations
Please note that, following the logic you described and using the input text you provided, the output string will have a blank space as last character
Also note that if multiple # are presente in the input text, then the first occurrence will be used.
Last index [Update]
I am adding this new section to answer the question you posted in the comments.
If you have a text like this
let text = "hello #tom #mark #mathias"
and you want the index of the last occurrency of "#" you can write
if let index = text.range(of: "#", options: .backwards)?.lowerBound {
print(index)
}
Try regular expressions, they are much safer (if you know what you are doing...)
let hello2 = "hello, how are you #tom, #my #next #victim?"
let deletedStringsAfterAtSign = hello2.replacingOccurrences(of: "#\\w+", with: "", options: .regularExpression, range: nil)
print(deletedStringsAfterAtSign)
//prints "hello, how are you , ?"
And this code removes exactly what you need and leaves the characters after the strings clear, so you can see the , and ? still being there. :)
EDIT: what you asked in comments to this answer:
let hello2 = "hello, how are you #tom, #my #next #victim?"
if let elementIwannaAfterEveryAtSign = hello2.components(separatedBy: " #").last
{
let deletedStringsAfterAtSign = hello2.replacingOccurrences(of: "#\\w+", with: elementIwannaAfterEveryAtSign, options: .regularExpression, range: nil)
print(deletedStringsAfterAtSign)
//prints hello, how are you victim?, victim? victim? victim??
}
I'm using this code to find the NSRange and text content of the string contents of a NSTextField.
nstext.enumerateSubstringsInRange(NSMakeRange(0, nstext.length),
options: NSStringEnumerationOptions.ByWords, usingBlock: {
(substring, substringRange, _, _) -> () in
//Do something with substring and substringRange
}
The problem is that NSStringEnumerationOptions.ByWords ignores punctuation, so that
Stop clubbing, baby seals
becomes
"Stop" "clubbing" "baby" "seals"
not
"Stop" "clubbing," "baby" "seals
If all else fails I could just check the characters before or after a given word and see if they are on the exempted list (where would I find which characters .ByWords exempts?); but there must be a more elegant solution.
How can I find the NSRanges of a set of words, from a string which includes the punctuation as part of the word?
You can use componentsSeparatedByString instead
var arr = nstext.componentsSeparatedByString(" ")
Output :
"Stop" "clubbing," "baby" "seals
Inspired by Richa's answer, I used componentsSeparatedByString(" "). I had to add a bit of code to make it work for me, since I wanted the NSRanges from the output. I also wanted it to still work if there were two instances of the same word - e.g. 'please please stop clubbing, baby seals'.
Here's what I did:
var words: [String] = []
var ranges: [NSRange] = []
//nstext is a String I converted to a NSString
words = nstext.componentsSeparatedByString(" ")
//apologies for the poor naming
var nstextLessWordsWeHaveRangesFor = nstext
for word in words
{
let range:NSRange = nstextLessWordsWeHaveRangesFor.rangeOfString(word)
ranges.append(range)
//create a string the same length as word so that the 'ranges' don't change in the future (if I just replace it with "" then the future ranges will be wrong after removing the substring)
var fillerString:String = ""
for var i=0;i<word.characters.count;++i{
fillerString = fillerString.stringByAppendingString(" ")
}
nstextLessWordsWeHaveRangesFor = nstextLessWordsWeHaveRangesFor.stringByReplacingCharactersInRange(range, withString: fillerString)
}