ios - Question on how to split a string into an array of desired strings in Swift

Question

I have a question.

There are several ways to divide a string into a string array.

First of all, the way I made a string into a string array is,

let str = "F'2R'UU2"
let strArr: [String] = str.map { String($0) }
//strArr => ["F", "'", "2", "R", "'", "U", "U", "2"]

It turns into a string array like this

But I would like to divide based on the uppercase alphabet. For example, if you divide the string F2, it becomes ["F2"] instead of ["F", "2"], and if you divide the string F'2, it becomes ["F", "'", "2"] instead of ["F'2"]

The result I want is,

let str = "F'2R'UU2"
<<<str to strArr>>>
//strArr => ["F'2", "R'", "U", "U2"]

Please let me know!

Answer 1

You can use reduce to iterate the string over each character and either append it to an array if it is an uppercase letter or add it to the last element of the array otherwise

let str = "F'2R'UU2"

let res = str.reduce(into: [String]()) {
    if $1.isUppercase || $0.isEmpty {
        $0.append("($1)") 
    } else {
        $0[$0.count - 1] = $0.last! + "($1)"
    }
}