Escaping backslash in Swift

Question or problem in the Swift programming language:

I’m sending regular expressions to CloudKit as a String value and it doesn’t seem to like it, replacing \\by \. However, once I’m getting this value from my app I would like to retransform it in its original form, with \\instead of \.

I don’t know how to manage this kind of escaped characters in Swift because I cannot even set a String with a \ in my code but I’m still able to manage them when getting them from CloudKit. Here is an example of String:

var onlyOneBackslash: String = valueFromCloudKit
print(onlyOneBackslash) // booking\.com

How to escape the backslash to transform booking\.com into booking\\.com?

How to solve the problem:

Solution 1:

The double backslash exists only in your code, it is a convention of the compiler. It never exists in the string itself, just in the Swift code.

If you want a double backslash in the string you need to have four backslashes in your code. Or use a String method to replace single backslashes with double backslashes.

Code example:

let originalString = "1\\2"
print("originalString: \(originalString)")
let newString = originalString.stringByReplacingOccurrencesOfString("\\", withString: "\\\\", options: .LiteralSearch, range: nil)
print("newString: \(newString)")

Output:

originalString: 1\2  
newString: 1\\2  

Solution 2:

Swift 5 version

let originalString = "1\\2"
print("originalString: \(originalString)")
let newString = originalString.replacingOccurrences(of: "\\", with: "\\\\")
print("newString: \(newString)")
replacingOccurrences(of: "\\", with: "\\\\")

Output:

originalString: 1\2  
newString: 1\\2  

Hope this helps!