String replacing occurrences

Using Swift
1

I am facing a weird issue with Swift +4.0 String. Here is a breakdown of the issue.

Let's assume we have a string:
var ourStr = "@p@P|Bl@[BACKSLASH]Fbk@XO[BACKSLASH]d@V[BACKSLASH][BACKSLASH]c@"

Here, we have 4 [BACKSLASH]s in our String. Our task is to replace each occurrence of [BACKSLASH] with a real backslash \.

We start by figuring out how we will implement this in our AwesomePlayground.playground:

ourStr = ourStr.replacingOccurrences(of: "[BACKSLASH]", with: "\\")
print(ourStr) // prints @p@P|Bl@\Fbk@XO\d@V\\c@

Works great, let's implement this in our AwesomeProject.xcodeproj

ourStr = ourStr.replacingOccurrences(of: "[BACKSLASH]", with: "\\")
print(ourStr) // prints @p@P|Bl@\\Fbk@XO\\d@V\\\\c@

This is completely unexpected! We just test this out in the playground and it's working perfectly fine!
In the xcodeproj it replaced the [BACKSLASH] with 2 backslashes, while in the playground it knows that one is escaping character.

I solved it by using NSString replacingOccurrences method. But, I believe there is something wrong going there.

2

Which version of Swift and/or Xcode are you using? I get the same result whether in a Playground or in a compiled app.

4

I tried on Xcode Version 9.2 and Xcode Version 9.3

5

Is ourStr at fault, or the print output? (What is the value of ourStr.count in each case?)

6

The unerlying string data is the same. It's 'just' a matter of how it is presented by Xcode in the console output here and there. I would suggest filing a bug against Xcode. It's not a Swift issue in itself.

7

I cannot reproduce this effect in Xcode 9.3b4 with the default toolchain. After running the Xcode project, I see:

@p@P|Bl@\Fbk@XO\d@V\\c@
Program ended with exit code: 0
1 Like
8

You're right! I tried that out with both, it should the same count for both cases.

9

You're right! It's Xcode bug, not Swift.
Thank you for your help.