Why I cannot use \ or backslash in a String in Swift?-CodePudding

I have a string like this in below and I want replace space with backslash and space.

let test: String = "Hello world".replacingOccurrences(of: " ", with: "\ ")
print(test)

But Xcode make error of :

Invalid escape sequence in literal

The code in up is working for any other character or words, but does not for backslash. Why?

CodePudding user response：

Backslash is used to escape characters. So to print a backslash itself, you need to escape it. Use \\.

CodePudding user response：

For Swift 5 or later you can avoid needing to escape backslashes using the enhanced string delimiters:

let backSlashSpace = #"\ "#

If you need String interpolation as well:

let value = 5
let backSlashSpaceWithValue = #"\\#(value) "#
print(backSlashSpaceWithValue) //  \5

You can use as many pound signs as you wish. Just make sure to mach the same amount in you string interpolation:

let value = 5
let backSlashSpaceWithValue = ###"\\###(value) "###
print(backSlashSpaceWithValue) //  \5

Note: If you would like more info about this already implemented Swift evolution proposal SE-0200 Enhancing String Literals Delimiters to Support Raw Text