How to get All the characters before a specific character while starting from the last index in Swift5?

Question

I have checked all the posts regarding string and substrings but I can't find any solution for my problem. Say I have a string "ABCD/EFG" Or "A/Ef". Now I want to get all the characters after "/" and I want to do it by only start reading from the last index. (Output: "EFG", "Ef"). Thanks

Answer 1

You got a few options:

1. Split on "/" and keep the last component:

let text = "ABCD/EFG"

if text.contains("/"), let last = text.components(separatedBy: "/").last {
    print(last) // => EFG
}

2. If your strings are URLs (or have similar structure) you can make URL do it for you:

let text = "A/Ef"

if text.contains("/"), let last = URL(string: text)?.lastPathComponent {
    print(last) // => Ef
}

Note: I'm only checking for "/" presence to avoid returning matches on strings that don't have a slash. If you are parsing URLs then you probably do not need this check.

Answer 2

You can use String lastIndex(of:) method to find the last occurrence of your slash character, get the index after that index limited by the string endIndex and get the substring from that index forward:

let str = "ABCD/EFG"
if let lastIndex = str.lastIndex(of: "/"),
    let index = str.index(lastIndex, offsetBy: 1, limitedBy: str.endIndex) {
    let substring = str[index...]  // "EFG"
    // if you need a string
    let string = String(str[index...])  // "EFG"
}

or as suggested by @MartinR using string range(of:) (this needs Foundation framework):

if let index = str.range(of: "/", options: .backwards)?.upperBound {
    // ...
}