import Foundation
let pattern = #"\b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}[0-9]\b|\b4[0-9][0-9]{11}\b|\b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}(?:[0-9]{4})?$\b|\b4[0-9][0-9]{14}\b|\b(4[0-9]{3}[ -])([0-9]{4}[ -]){3}(?:[0-9]{3})?$\b|\b4[0-9][0-9]{17}\b"#
let regex = try! NSRegularExpression(pattern: pattern, options: .anchorsMatchLines)
let testString = #"""
Visa:
Requirements: Visa numbers start with the number 4 and have either 13, 16, or 19 digits (new cards).
Pattern Parts:
Starts with number 4 and 13 length:
1) \b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}[0-9]\b|\b4[0-9][0-9]{11}\b
Starts with number 4 and 16 length:
2) \b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}(?:[0-9]{4})?$\b|\b4[0-9][0-9]{14}\b
Starts with number 4 and 19 length:
3) \b(4[0-9]{3}[ -])([0-9]{4}[ -]){3}(?:[0-9]{3})?$\b|\b4[0-9][0-9]{17}\b
Combining 1-3 to form one pattern:
\b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}[0-9]\b|\b4[0-9][0-9]{11}\b|\b(4[0-9]{3}[ -])([0-9]{4}[ -]){2}(?:[0-9]{4})?$\b|\b4[0-9][0-9]{14}\b|\b(4[0-9]{3}[ -])([0-9]{4}[ -]){3}(?:[0-9]{3})?$\b|\b4[0-9][0-9]{17}\b
Test Cases:
Should fire:
13 length, no space, start with 4 4123123412341
13 length, dashes, start with 4 4123-1234-1234-1
13 length, spaces, start with 4 4123 1234 1234 1
16 length, no space, start with 4 4221123412341234
16 length, dashes, start with 4 4221-1234-1234-1234
16 length, spaces, start with 4 4221 1234 1234 1234
19 length, no space, start with 4 4241123412341234123
19 length, dashes, start with 4 4241-1234-1234-1234-123
19 length, spaces, start with 4 4241 1234 1234 1234-123
Should not fire:
16 length, no space, not start with 51-55 5623123412341234
16 length, dashes, not start with 51-55 5623-1234-1234-1234
16 length, spaces, not start with 51-55 5623 1234 1234 1234
16 length, no space, not start with 2221-2720 2220123412341234
16 length, dashes, not start with 2221-2720 2220-1234-1234-1234
16 length, spaces, not start with 2221-2720 2220 1234 1234 1234
Non 16 length, matches 51 pattern start 5123-1234-1234-123
Non 16 length, matches 2221 pattern start 2221-1234-1234-123
Malformed, matches 51 pattern start 51-2312-34-1234-1234
"""#
let stringRange = NSRange(location: 0, length: testString.utf16.count)
let matches = regex.matches(in: testString, range: stringRange)
var result: [[String]] = []
for match in matches {
var groups: [String] = []
for rangeIndex in 1 ..< match.numberOfRanges {
let nsRange = match.range(at: rangeIndex)
guard !NSEqualRanges(nsRange, NSMakeRange(NSNotFound, 0)) else { continue }
let string = (testString as NSString).substring(with: nsRange)
groups.append(string)
}
if !groups.isEmpty {
result.append(groups)
}
}
print(result)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Swift 5.2, please visit: https://developer.apple.com/documentation/foundation/nsregularexpression