CODEWITHSUNDEEP
stringswift
arj
arj

Reputation: 141

Swift - Find character at several positions within string

In Swift, with the following string: "this is a string", how to obtain an array of the indexes where the character " " (space) is present in the string?

Desired result: [4,7,9]

I've tried:

let spaces: NSRange = full_string.rangeOfString(" ")

But that only returns 4, not all the indexes.

Any idea?

Upvotes: 4

Views: 396

Answers (2)

Aaron Brager
Aaron Brager

Reputation: 66292

Here's a simple approach — updated for Swift 5.6 (Xcode 13):

let string = "this is a string"

let offsets = string
    .enumerated()
    .filter { $0.element == " " }
    .map { $0.offset }

print(offsets) // [4, 7, 9]

How it works:

  • enumerated() enumerates the characters of the string
  • filter removes the characters for which the characters aren't spaces
  • map converts the array of tuples to an array of just the indices

Upvotes: 8

vadian
vadian

Reputation: 285170

A solution for Swift 1.2 using Regex

func searchPattern(pattern : String, inString string : String) -> [Int]?
{
  let regex = NSRegularExpression(pattern: pattern, options: NSRegularExpressionOptions(), error: nil)
  return regex?.matchesInString(string, options: NSMatchingOptions(), range: NSRange(location:0, length:count(string)))
               .map { ($0 as! NSTextCheckingResult).range.location }
}

let string = "this is a string"

searchPattern("\\s\\S", inString : string) // [4, 7, 9]
searchPattern("i", inString : string) // [2, 5, 13]

Upvotes: 0

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