CODEWITHSUNDEEP
iosstringswift
Harout360
Harout360

Reputation: 939

How to remove special characters from string in Swift 2?

The answer in How to strip special characters out of string? is not working.

Here is what I got and it gives me an error 

func removeSpecialCharsFromString(str: String) -> String {
    let chars: Set<String> = Set(arrayLiteral: "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-*=(),.:!_")

    return String(str.characters.filter { chars.contains($0) }) //error here at $0
}

The error at $0 says

_Element (aka Character) cannot be converted to expected argument type 'String'.

Upvotes: 53

Views: 57971

Answers (6)

Rodolfo Teixeira
Rodolfo Teixeira

Reputation: 11

without removing spaces between words

extension String {
    var removeSpecialCharacters: String {
        return self.components(separatedBy: CharacterSet.alphanumerics.inverted).filter({ !$0.isEmpty }).joined(separator: " ")
    }
}

Upvotes: 0

matt
matt

Reputation: 535304

Like this:

func removeSpecialCharsFromString(text: String) -> String {
    let okayChars : Set<Character> = 
        Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-*=(),.:!_".characters)
    return String(text.characters.filter {okayChars.contains($0) })
}

And here's how to test:

let s = removeSpecialCharsFromString("père") // "pre"

Upvotes: 79

Ben Lin
Ben Lin

Reputation: 109

Try this:

someString.removeAll(where: {$0.isPunctuation})

Upvotes: 11

Bisca
Bisca

Reputation: 6763

I think that a cleaner solution could be this approach:

extension String {
    var alphanumeric: String {
        return self.components(separatedBy: CharacterSet.alphanumerics.inverted).joined().lowercased()
    }
}

Upvotes: 27

Yaroslav Dukal
Yaroslav Dukal

Reputation: 3932

SWIFT 4: 

func removeSpecialCharsFromString(text: String) -> String {
    let okayChars = Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-=().!_")
    return text.filter {okayChars.contains($0) }
}

More cleaner way:

extension String {

    var stripped: String {
        let okayChars = Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-=().!_")
        return self.filter {okayChars.contains($0) }
    }
}

Use this extension like:

let myCleanString = "some.Text@#$".stripped

Output: "some.Text"

Upvotes: 52

Martin R
Martin R

Reputation: 539795

In Swift 1.2,

let chars = Set("abcde...")

created a set containing all characters from the given string. In Swift 2.0 this has to be done as

let chars = Set("abcde...".characters)

The reason is that a string itself does no longer conform to SequenceType, you have to use the characters view explicitly.

With that change, your method compiles and works as expected:

func removeSpecialCharsFromString(str: String) -> String {
    let chars = Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-*=(),.:!_".characters)
    return String(str.characters.filter { chars.contains($0) })
}

let cleaned = removeSpecialCharsFromString("ab€xy")
print(cleaned) // abxy

Remark: @Kametrixom suggested to create the set only once. So if there is performance issue with the above method you can either move the declaration of the set outside of the function, or make it a local static:

func removeSpecialCharsFromString(str: String) -> String {
    struct Constants {
        static let validChars = Set("abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890+-*=(),.:!_".characters)
    }
    return String(str.characters.filter { Constants.validChars.contains($0) })
}

Upvotes: 8

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