SwiftString.swift

// Approach #1
let fruit = ["012Apple", "03218Banana", "11 Orange"]
var stringsOnly: [String] = []
for f in fruit {
    stringsOnly.append(f.stringByTrimmingCharactersInSet(NSCharacterSet.letterCharacterSet().invertedSet))
}

// Approach #2
let fruits = ["012Apple", "03218Banana", "11 Orange"]
var stringOnly = [String]()

for fruit in fruits {
    if let match = fruit.rangeOfString("[a-zA-Z]+", options: .RegularExpressionSearch) {
        stringOnly.append(fruit.substringWithRange(match))
    }
}
print(stringOnly) // Apple, Banana, Orange

// result: ["Apple", "Banana", "Orange"]
// Credit: http://stackoverflow.com/questions/35963208/trim-numerical-and-separator-values-from-the-beginning-of-strings-in-swift