Swift: Separate String into String Array and Append Separator

Question

How would I split a string to include the separators?

Lets say I had a string such as...

let myString = "apple banana orange grapes"

If I used

let separatedString = myString.componentsSeparatedByString(" ")

my resulting array would be

["apple","banana","orange","grapes"]

How would I achieve a result of

["apple ","banana ","orange ","grapes"]

Why do you want to do this? Do you have a specific reason for the extra space. If you really need it, you could also add the space later when your array is used. — Asdrubal
– Asdrubal, Commented Jul 14, 2016 at 17:59
@Asdrubal I'd like to keep the spaces because I'd like to keep track of the character count / location of each word from the original string. I also just wanted to avoid using NSRanges — bremmm
– bremmm, Commented Jul 14, 2016 at 18:10
Would something like this be of interest to you? github.com/mattgemmell/MGWordCounter — Asdrubal
– Asdrubal, Commented Jul 14, 2016 at 18:24

Alex Wayne · Accepted Answer · 2016-07-14 17:49:49Z

2

array.map lets you process the resulting array an add the space back in.

let separatedString = myString
  .componentsSeparatedByString(" ")
  .map { "\($0) " }

That last line iterates over all strings in the split up array and puts them in $0, and returns a new string with the space added back in which gets used as the replacement for the original string.

edited Jul 14, 2016 at 17:49

answered Jul 14, 2016 at 17:47

Alex Wayne

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2 Comments

bremmm Over a year ago

Would there be a way to adjust this answer for if there were multiple component separators? If the accepted separators were " " and "\n", how would you know which to insert?

Alex Wayne Over a year ago

Yeah that gets trickier. You'd need multiple passes, or regular expressions.

vadian · Accepted Answer · 2016-07-14 18:36:18Z

1

Alternative using regular expression:

let myString = "apple banana orange grapes"
let pattern = "\\w+\\s?"
let regex  = try! NSRegularExpression(pattern: pattern, options: [])
let matches = regex.matchesInString(myString, options:[], range: NSMakeRange(0, myString.characters.count))
  .map { (myString as NSString).substringWithRange($0.range)}
print(matches) // -> ["apple ", "banana ", "orange ", "grapes"]

answered Jul 14, 2016 at 18:36

vadian

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2 Comments

bremmm Over a year ago

from another comment in this thread, Would there be a way to adjust this answer for if there were multiple component separators? If the accepted separators were " " and "\n", how would you know which to insert?

vadian Over a year ago

@bremmm This regex considers space characters as well as \t, \n, \r. The pattern does: Catch any alphanumeric character (one or more) followed by an (optional) whitespace character. There is no insertion, the respective whitespace character after the match is included.

Luca Angeletti · Accepted Answer · 2016-07-14 20:47:01Z

1

Solution

Since you updated your question, it looks now you no longer want a new space on the last word.

So here's my updated code

let text = "apple banana orange grapes"

let chunks: [String] = text
    .componentsSeparatedByString(" ")
    .reverse()
    .enumerate()
    .map { $0.element + ( $0.index == 0 ? "" : " ") }
    .reverse()

print(chunks) // ["apple ", "banana ", "orange ", "grapes"]

Multiple separators

Thank to @vadian for the suggestion

let text = "apple banana\norange grapes"

let chunks: [String] = text
    .componentsSeparatedByCharactersInSet(.whitespaceAndNewlineCharacterSet())
    .reverse()
    .enumerate()
    .map { $0.element + ( $0.index == 0 ? "" : " ") }
    .reverse()

print(chunks) // ["apple ", "banana ", "orange ", "grapes"]

edited Jul 14, 2016 at 20:47

answered Jul 14, 2016 at 17:48

Luca Angeletti

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4 Comments

bremmm Over a year ago

from another comment of mine in this thread, Would there be a way to adjust this answer for if there were multiple component separators? If the accepted separators were " " and "\n", how would you know which to insert?

Luca Angeletti Over a year ago

@bremmm: Please see the Multiple separators section in my answer

vadian Over a year ago

@appzYourLife componentsSeparatedByCharactersFromSet with whitespaceAndNewlineCharacterSet for multiple separators might be more appropriate.

Luca Angeletti Over a year ago

@vadian: You are totally right. Thank your for the hint!

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