How to detect multiple occurrences of a word within a string

Question

I have been looking around for some time now and am wondering how to detect multiple locations of a substring within a larger string. For example:

let text = "Hello, playground. Hello, playground"
let range: Range<String.Index> = text.rangeOfString("playground")! //outputs 7...<17
let index: Int = text.startIndex.distanceTo(range.startIndex) //outputs 7, the location of the first "playground"

I use this code to detect the first location that the substring appears within a string, but its it possible to detect the location of the second occurrence of "playground" and then the third and so on and so forth?

Objective-C answers here, but the logic applies the same way: [Number of occurrences of a substring in an NSString?](http://stackoverflow.com/questions/2166809/number-of-occurrences-of-a-substring-in-an-nsstring) — JAL, Mar 02 '16 at 22:40

score 8 · Accepted Answer · edited Apr 20 '21 at 10:17

8

This should get you an array of NSRanges with "playground"

let regex = try! NSRegularExpression(pattern: "playground", options: [.caseInsensitive])
let items = regex.matches(in: text, options: [], range: NSRange(location: 0, length: (text as NSString).length))
let ranges: [NSRange] = items.map{$0.range}

Then to get the strings:

let occurrences: [String] = ranges.map{String((text as NSString).substring(with:$0))}

edited Apr 20 '21 at 10:17

nalexn

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answered Mar 02 '16 at 22:25

GetSwifty

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Updated. The ranges contain the locations, the occurrences contain the strings themselves. – GetSwifty Mar 02 '16 at 22:42

score 1 · Answer 2 · answered Aug 29 '18 at 11:43

Swift 4

let regex = try! NSRegularExpression(pattern: fullNameArr[1], options: [.caseInsensitive])
let items = regex.matches(in: str, options: [], range: NSRange(location: 0, length: str.count))
let ranges: [NSRange] = items.map{$0.range}
let occurrences: [String] = ranges.map{String((str as NSString).substring(with: $0))}

How to detect multiple occurrences of a word within a string

2 Answers2