How to remove whitespaces in strings in Swift?

Question

This works

let replaced = String(map(aString.generate()) {
    $0 == " " ? "-" : $0 })

and this doesn't

let replaced = String(map(aString.generate()) {
    $0 == " " ? "" : $0 })

Why?

score 19 · Answer 1 · answered Sep 15 '19 at 22:46

19

For Swift 5:

" spaces here ".replacingOccurrences(of: " ", with: "")

returns:

"spaceshere"

answered Sep 15 '19 at 22:46

Shaked Sayag

5,054
2
29
36

score 16 · Answer 2 · edited Dec 28 '19 at 18:51

Enumerating a string gives a sequence of characters, so $0 inside the closure has the type Character. This compiles

{ $0 == " " ? "-" : $0 }

because "-" in this context is interpreted as a character literal and therefore of the same type as $0. But

{ $0 == " " ? "" : $0 }

does not compile because "" is not a character literal (and in the conditional expression a ? b : c the operands b and c must have the same type).

You can fix that by converting $0 to a string:

{ $0 == " " ? "" : String($0) }

but now the mapping returns an array of strings instead of an array of characters. So instead of the String() constructor you have to join the results:

let replaced = "".join(map(aString) { $0 == " " ? "" : String($0) })
// Swift 2 / Xcode 7:
let replaced = "".join(aString.characters.map({ $0 == " " ? "" : String($0) }))

(Note that calling generate() explicitly is not needed.)

Of course the same result would also be achieved with

// Before Swift 3.0
let replaced = aString.stringByReplacingOccurrencesOfString(" ", withString: "")

// After Swift 3.0
let replaced = aString.replacingOccurrences(of: " ", with: "")

score 8 · Answer 3 · edited Jun 06 '20 at 15:37

8

If you want to remove white space from string then just pass string with stringByReplacingOccurrencesOfString function like below,

let replacedString = string.replacingOccurrences(of: " ", with: "")

For Text Fields, you can apply directly object of UITextField,

let replacedString = textField.text!.replacingOccurrences(of: " ", with: "")

edited Jun 06 '20 at 15:37

liudasbar

107
4
9

answered Mar 15 '16 at 12:01

iAnkit

1,870
18
24

score 7 · Answer 4 · answered May 03 '16 at 01:42

7

This should work as of Swift 2.2:

let replaced = String(aString.characters.filter {$0 != " "})

answered May 03 '16 at 01:42

EFC

1,770
17
38

I worked with numbers with spaces, I don't know why, but just this variant removes spaces in decimal numbers, thanks! – Alexander B Mar 09 '21 at 15:53

score 5 · Answer 5 · answered Jun 29 '15 at 22:59

If you want to delete whitespaces before and after a string, which is very useful in user input forms, you can use:

let replaced = aString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())

You can apply it directly on a textfield as well.

score 4 · Answer 6 · answered May 29 '17 at 11:56

If you want to remove all whitespaces anywhere in the String I did come up with this solution for Swift 3.0:

let number = "+000 000 000"
let nonWhiteCharacters = number.unicodeScalars.filter {
    false == NSCharacterSet.whitespacesAndNewlines.contains($0)
}.map(Character.init)
let whitespacelessNumber = String(nonWhiteCharacters)

or even better (you will need generic extension on Sequence):

extension Sequence {
    public func reduce<Result>(_ result: (Self) throws -> Result) rethrows -> Result {
        return try result(self)
    }
}

and then you can write:

let whitespacelessNumber = number.unicodeScalars.filter {
    false == NSCharacterSet.whitespacesAndNewlines.contains($0)
}.map(Character.init).reduce { String($0) }

where you can also replace NSCharacterSet.whitespacesAndNewlines for any of other character sets:

NSCharacterSet.controlCharacters
NSCharacterSet.whitespaces
NSCharacterSet.whitespacesAndNewlines
NSCharacterSet.decimalDigits
NSCharacterSet.letters
NSCharacterSet.lowercaseLetters
NSCharacterSet.uppercaseLetters
NSCharacterSet.nonBaseCharacters
NSCharacterSet.alphanumerics
NSCharacterSet.decomposables
NSCharacterSet.illegalCharacters
NSCharacterSet.punctuationCharacters
NSCharacterSet.capitalizedLetters
NSCharacterSet.symbols
NSCharacterSet.newline

score 3 · Answer 7 · answered Feb 16 '15 at 19:36

You are mapping thus the number of elements should be preserved. In the second case you remove elements. Your example will fail even in case you replace " " with --.

You might prefer using filter:

let replaced = String(filter(aString.generate()) { $0 != " "})

score 2 · Answer 8 · answered Jul 01 '15 at 15:06

2

try this one:

let strArray0 = strArray1.map { $0.stringByTrimmingCharactersInSet(.whitespaceAndNewlineCharacterSet()) }

Hope this helps

answered Jul 01 '15 at 15:06

Daniel

347
2
11

score 2 · Answer 9 · answered Aug 09 '19 at 07:58

2

None of the previous answers where Swifty enough for me, so I ended up with this using Swift 5:

let nonWhitespaceString = String(whitespaceString.compactMap({ $0.isWhitespace ? nil : $0 })

answered Aug 09 '19 at 07:58

juhan_h

3,865
3
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score 1 · Answer 10 · answered Mar 30 '17 at 11:11

In Swift 3.0 DO as

func RemoveWhiteSpace(aString:String) -> String
    {
        let replaced = aString.trimmingCharacters(in: NSCharacterSet.whitespaces)
        return replaced
    }

And use like this

let nonWhiteSpaceStr = self.RemoveWhiteSpace(aString: "I have white Space        ")

How to remove whitespaces in strings in Swift?

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