How to remove multiple spaces in Strings with Swift 2

Question

Until Swift 2 I used this extension to remove multiple whitespaces:

func condenseWhitespace() -> String {
        let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter({!Swift.isEmpty($0)})
        return " ".join(components)
}

but with Swift 2 now I get the error

Cannot invoke 'isEmpty' with an argument list of type '(String)'

How could I now remove multiple spaces with Swift 2? Thnx!

Napery

Answer 1

In Swift 2, join has become joinWithSeparator and you call it on the array.

In filter, isEmpty should be called on the current iteration item $0.

To replace whitespaces and newline characters with unique space characters as in your question:

extension String {
    func condenseWhitespace() -> String {
        let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
        return components.filter { !$0.isEmpty }.joinWithSeparator(" ")
    }
}

let result = "Hello  World.\nHello!".condenseWhitespace()  // "Hello World. Hello!"

Because your function does not take any parameter you could make it a property instead:

extension String {
    var condensedWhitespace: String {
        let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
        return components.filter { !$0.isEmpty }.joinWithSeparator(" ")
    }
}

let result = "Hello  World.\nHello!".condensedWhitespace  // "Hello World. Hello!"

---

In Swift 3 there's even more changes.

Function:

extension String {
    func condenseWhitespace() -> String {
        let components = self.components(separatedBy: NSCharacterSet.whitespacesAndNewlines)
        return components.filter { !$0.isEmpty }.joined(separator: " ")
    }
}

let result = "Hello  World.\nHello!".condenseWhitespace()

Property:

extension String {
    var condensedWhitespace: String {
        let components = self.components(separatedBy: NSCharacterSet.whitespacesAndNewlines)
        return components.filter { !$0.isEmpty }.joined(separator: " ")
    }
}

let result = "Hello  World.\nHello!".condensedWhitespace

In Swift 4.2 NSCharacterSet is now CharacterSet, and you can omit and use dot syntax:

extension String {
    func condenseWhitespace() -> String {
        let components = self.components(separatedBy: .whitespacesAndNewlines)
        return components.filter { !$0.isEmpty }.joined(separator: " ")
    }
}

let result = "Hello  World.\nHello!".condenseWhitespace()  // "Hello World. Hello!"

Vidavidal

be careful, if you want to make it work with whitespacesAndNewlines you need to manage new lines as new lines and not " " when you join. ** func condenseWhitespace() -> String { let components = self.components(separatedBy: .whitespaces) let tmpstr = components.filter { !$0.isEmpty }.joined(separator: " ") let components2 = tmpstr.components(separatedBy: .newlines) return components2.filter { !$0.isEmpty }.joined(separator: "\n") }** – Rightism

The extension works great in Swift 5. Lifesaving code! Thank you :) – Carter

Answer 2

Splitting the string to an array and then joining again is not memory-efficient. It takes a lot of memory. The best way in this case is to scan the given string and perform operations on it using regular expressions. The solution is given below:

Swift 4.x

extension String {
    
    func removeExtraSpaces() -> String {
        return self.replacingOccurrences(of: "[\\s\n]+", with: " ", options: .regularExpression, range: nil)
    }
    
}

Usage:

let originalString = "Hello   world! \n\n I am   here!"
let processedString = originalString.removeExtraSpaces()
print(processedString)

Output:

"Hello world! I am here!"

You can do more according to your own requirements, but my point here is to use regular expressions rather than creating arrays which would consume lots of memory.

Pretrice

Thank you! This is better than creating unnecessary arrays. – Morrill

@JeanNicolas For That, you can use .trimmingCharacters(in: .whitespacesAndNewlines) function by adding it to your extension. The Above solution is reducing more than 1 spaces or newlines to 1 space. I will really appreciate if you can make this functionality more responsible to trim the sting also. Thanks :-) – Pretrice

Answer 3

Cleanest version. Documented, memory efficient, extremely easy to use.

extension String {

    /// Returns a condensed string, with no extra whitespaces and no new lines.
    var condensed: String {
        return replacingOccurrences(of: "[\\s\n]+", with: " ", options: .regularExpression, range: nil)
    }

    /// Returns a condensed string, with no whitespaces at all and no new lines.
    var extraCondensed: String {
        return replacingOccurrences(of: "[\\s\n]+", with: "", options: .regularExpression, range: nil)
    }

}

Usage:

let a = " Hello\n  I am  a string  ".condensed
let b = " Hello\n  I am  a string  ".extraCondensed

Output:

a: "Hello I am a string"

b: "HelloIamastring"

Paryavi

Answer 4

SWIFT 3: Cleaner version

extension String {
    var condensedWhitespace: String {
        let components = self.components(separatedBy: .whitespacesAndNewlines)
        return components.filter { !$0.isEmpty }.joined(separator: " ")
    }
}

Denude

What the advantage of using var over func? – Jacoby

I don't think it's making any difference. Just saving you () – Denude

Answer 5

Here is mine: How it's actually worked.

extension String {

    func removeExtraSpaces() -> String {
        var data  = ""
        var numberOfSpace = 0
        let items = self.getComponents(separatedBy: " ")
        for item in items{
            if item == " "{
                numberOfSpace = numberOfSpace + 1
            }else{
                numberOfSpace = 0
            }
            if numberOfSpace == 1 || numberOfSpace == 0 {
                data =  data + item
                //data.append(item)
            }
        }
        return data
    }
} 

Usages

 var message = "What  is the    purpose   of life?"
 message = message.removeExtraSpaces()
 print(message)

Output:

What is the purpose of life?

Experience

Answer 6

Code below work for me. I needed to remove EXTRA spaces from string.

var example = "    Hello       world   "

func removeSpacers(from word: String) -> String {
var finalResult = ""
var spacesCount = 0

let trimmed = word.trimmingCharacters(in: .whitespaces)
let components = trimmed.components(separatedBy: " ")

// if we have not any spaces we returning trimmed string
guard components.contains(where: { $0 == "" }) else { return trimmed }
components.forEach {
    // because .components returning ""(empty string)
    if $0 == "" {
        spacesCount += 1
    } else {
        // if another element not space, we could add space(the space between words)
        if spacesCount != 0 {
            spacesCount = 0
            finalResult.append(" ")
        }
    }
    // so if we have no spaces we could add word no result string
    if spacesCount == 0 {
        finalResult.append($0)
    }
}
return finalResult

}

I make a couple of tests, its work.

 func testRemoveSpaceFromStringWithSpacesOnCenter() {
    // given
    let string = "Hello     world"

    // when
    let result = pfromatter.removeSpaces(from: string)

    // then
    let expected = "Hello world"
    XCTAssertEqual(expected, result)
}

func testRemoveSpaceFromStringWithSpacesOnSide() {
    // given
    let string = " Hello world "

    // when
    let result = pfromatter.removeSpaces(from: string)

    // then
    let expected = "Hello world"
    XCTAssertEqual(expected, result)
}

Caroncarotene

Answer 7

var str = "Hello  World.\nHello!"

if let regex = try? NSRegularExpression(pattern: "\\s+", options:NSRegularExpression.Options.caseInsensitive)
{
    str = regex.stringByReplacingMatches(in: str, options: [], range: NSMakeRange(0, str.count), withTemplate: " ")

}

Cathey

Answer 8

If you want to remove duplicate whitespace and any leading/trailing whitespace in one go, you can use the below solution:

extension String {
    func trimmingExtraWhitespace() -> String {
        return self.replacingOccurrences(of: "(?<=\\s)\\s+|\\s+(?=$)|(?<=^)\\s+", 
                                         with: "", 
                                         options: .regularExpression)
    }
}

What it does:

• (?<=\\s)\\s+ matches all whitespace preceded by a space
• \\s+(?=$) matches all whitespace at the end of a string
• (?<=^)\\s+ matches all whitespace at the beginning of a string

Remarks:

• \s in regex includes spaces, tabs and line breaks, so you don't need to explicitly specify \n.
• You need to escape \s in Swift, thus the double backward slash \\

Example:

var originalString = "  Hello   world  "
var processedString = originalString.trimmingExtraWhitespace()
print("Original: \(originalString)")
print("Processed: \(processedString)")

Output:

Original:   Hello   world  
Processed: Hello world

Gaia