Replace in Swift

To replace a substring within a string in Swift, you can use the replacingOccurrences(of:with:) method. This method takes in two arguments: the substring to be replaced and the replacement substring. It returns a new string with all occurrences of the specified substring replaced with the replacement substring. Here is an example:

let originalString = "Hello, World!"
let newString = originalString.replacingOccurrences(of: "o", with: "e")
print(newString) // Prints "Helle, Werld!"

In this example, we replace all occurrences of the letter "o" with the letter "e" in the string "Hello, World!"

You can also use this method to replace only a specific occurrence of the substring by providing a range of the string to replace. Here's an example:

let originalString = "The quick brown fox jumps over the lazy dog"
var newString = originalString
if let range = newString.range(of: "fox") {
    newString.replaceSubrange(range, with: "puma")
}
print(newString) // Prints "The quick brown puma jumps over the lazy dog"

In this example, we replace only the first occurrence of the substring "fox" with "puma" by using the range(of:) method to find the range of the substring and then using replaceSubrange(_:with:) to replace the substring within that range.