Case-sensitive string replacements in Swift
In this post, we’ll discuss how to replace all occurences of a string in another string and then create an extension that allows for easier case-sensitive replacements.
The basics
We can use replacingOccurrences(of:with:) to replace all occurences of a certain string within another string:
let string = "This string contains text"
string.replacingOccurrences(of: "text", with: "characters")
// => "This string contains characters"
However, this will not perform a case-insensitive replacement, which means that
string.replacingOccurrences(of: "Text", with: "characters")
// => "This string contains text"
To allow for case-insensitive contains checks, you can provide a .caseInsensitive option:
string.replacingOccurrences(
of: "Text",
with: "characters",
options: .caseInsensitive
) // => "This string contains characters"
However, I think that the function name is too long and that options is tedious to use.
Extending String
We can create shorter and convenient String extensions to let us perform case-sensitive and case-insensitive replacements:
public extension String {
func replacing(
_ string: String,
with: String
) -> String {
replacingOccurrences(of: string, with: with)
}
func replacing(
_ string: String,
with: String,
caseSensitive: Bool
) -> String {
caseSensitive
? replacing(string, with: with)
: replacingOccurrences(
of: string,
with: with,
options: .caseInsensitive
)
}
}
We can now perform case-sensitive and case-insensitive contains checks the same way:
string.replacing("text", with: "characters")
string.replacing("Text", with: "characters", caseSensitive: true)
I like this since it lets me write a little less code when replacing strings in Swift.
Source Code
I have added these extensions to my SwiftUIKit library. You can find the source code here. Feel free to try it out and let me know what you think!