How to check whether a WHOLE string can be matches to regex? In Java is method String.matches(regex)
3 Answers
You need to use anchors, ^ (start of string anchor) and $ (end of string anchor), with range(of:options:range:locale:), passing the .regularExpression option:
import Foundation
let phoneNumber = "123-456-789"
let result = phoneNumber.range(of: "^\\d{3}-\\d{3}-\\d{3}$", options: .regularExpression) != nil
print(result)
Or, you may pass an array of options, [.regularExpression, .anchored], where .anchored will anchor the pattern at the start of the string only, and you will be able to omit ^, but still, $ will be required to anchor at the string end:
let result = phoneNumber.range(of: "\\d{3}-\\d{3}-\\d{3}$", options: [.regularExpression, .anchored]) != nil
See the online Swift demo
Also, using NSPredicate with MATCHES is an alternative here:
The left hand expression equals the right hand expression using a regex-style comparison according to ICU v3 (for more details see the ICU User Guide for Regular Expressions).
MATCHES actually anchors the regex match both at the start and end of the string (note this might not work in all Swift 3 builds):
let pattern = "\\d{3}-\\d{3}-\\d{3}"
let predicate = NSPredicate(format: "self MATCHES [c] %@", pattern)
let result = predicate.evaluate(with: "123-456-789")
Comments
What you are looking for is range(of:options:range:locale:) then you can then compare the result of range(of:option:) with whole range of comparing string..
Example:
let phoneNumber = "(999) 555-1111"
let wholeRange = phoneNumber.startIndex..<phoneNumber.endIndex
if let match = phoneNumber.range(of: "\\(?\\d{3}\\)?\\s\\d{3}-\\d{4}", options: .regularExpression), wholeRange == match {
print("Valid number")
}
else {
print("Invalid number")
}
//Valid number
Edit: You can also use NSPredicate and compare your string with evaluate(with:) method of its.
let pattern = "^\\(?\\d{3}\\)?\\s\\d{3}-\\d{4}$"
let predicate = NSPredicate(format: "self MATCHES [c] %@", pattern)
if predicate.evaluate(with: "(888) 555-1111") {
print("Valid")
}
else {
print("Invalid")
}
9 Comments
Wiktor Stribiżew
I think
"\\(?\\d{3}\\)?\\s\\d{3}-\\d{4}" will also allow partial matches. Add ^ and $ anchors on both sides of the pattern.
Nirav D
@WiktorStribiżew Edited answer
Wiktor Stribiżew
Yeah, I thought about that, too. I think there is still another way, but can't find a way to make NSPredicate work in Swift 3. It is really misfortunate that
.anchored only anchors at the string start.Nirav D
@WiktorStribiżew Thanks for remind me about
NSPredicate, edited answer with that alsoWiktor Stribiżew
No, it is not the only issue. Mabe the NSPredicate was not ready in Swift 3.0.2.
|
with little bit of edit
import Foundation
func matches(for regex: String, in text: String) -> Bool {
do {
let regex = try NSRegularExpression(pattern: regex)
let nsString = text as NSString
let results = regex.matches(in: text, range: NSRange(location: 0, length: nsString.length))
return !results.isEmpty
} catch let error {
print("invalid regex: \(error.localizedDescription)")
return false
}
}
Example usage from link above:
let string = "19320"
let matched = matches(for: "^[1-9]\\d*$", in: string)
print(matched) // will match
let string = "a19320"
let matched = matches(for: "^[1-9]\\d*$", in: string)
print(matched) // will not match
^and$anchors with your pattern? I mean, do you define the pattern or is it user-defined?^and$to define the start and end positions. There is.anchoredoption, but it works as/Ain PHP, only anchors at the start of the string.