I have these arrays :
ArrayEntr = ["Hello (40 km)", "Salut (20 km)", "Bonjour (30 km)", "Hi (35 km)"]
ArraySorted = ["20", "30", "35", "40"]
I would like to replace ArrayEntr in the same order as ArraySorted. In fact, I would like to sort ArrayEntr ascendantly with the number at the end
I've tried a few loops but I can't get it working as I want to.
Thank's a lot !
Since you know you're going to need to do this, plan ahead; form your original array as an array of string-Int tuples:
ArrayEntr = [("Hello (40 km)",40), ("Salut (20 km)",20), ("Bonjour (30 km)",30), ("Hi (35 km)",35)]
Now the problem is trivial: simply sort on the second member of each type, namely $0.1.
If you don't do that, you're going to have to somehow find the number buried in each string. You can do that, but you presumably had a number at some point, so it seems foolish to bury it in a string only to make it hard to get it back out again.
If you're getting this array from an external source which doesn't provide the numerical information along with the strings, you'll have to extract the numbers from them yourself. Of course if you had the numerical information to begin with at some point, you should've hung onto it as @matt says.
One way of getting the numerical information back out of your strings would be using flatMap on your array, followed by using stringByTrimmingCharactersInSet in order to trim away non-numerical characters from each end of the string. You can then attempt to create a double out of it in order to create a new array of (String, Double) tuples, and using flatMap to filter out the nil results. For example:
let strings = ["foobar", "Hello (45.5 km)", "George St. (39.5 km)", "Salut (20.45 km)", "Bonjour (30 km)", "Hi (35 km)"]
let stringsWithNumbers = strings.flatMap {str in
// trim away the non numerical characters, and attempt to create a double from the result
Double(str.stringByTrimmingCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet)).map {(string: str, number: $0)}
}
print(stringsWithNumbers) // [("Hello (45.5 km)", 45.5), ("George St. (39.5 km)", 39.5), ("Salut (20.45 km)", 20.449999999999999), ("Bonjour (30 km)", 30.0), ("Hi (35 km)", 35.0)]
Note that this won't work with strings with multiple numbers in (although I can't think of how you'd want to handle that situation anyway).
If you know that you're distances are always contained in rounded brackets, you could add some extra code in order to allow numbers outside the brackets, by first trimming the string down to the brackets, then trimming to the number. For example:
let strings = ["foobar", "5th Avenue (3 km)", "Hello (45.5 km)", "George St. (39.5 km)", "Salut (20.45 km)", "Bonjour (30 km)", "Hi (35 km)"]
let stringsWithNumbers:[(string:String, number:Double)] = strings.flatMap{str in
// the substring of the brackets
let brackets = str.stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "()").invertedSet)
// the number within the brackets
let num = brackets.stringByTrimmingCharactersInSet(NSCharacterSet.decimalDigitCharacterSet().invertedSet)
// attempt to create a double from the result
return Double(num).map {(string: str, number: $0)}
}
print(stringsWithNumbers) // [("5th Avenue (3 km)", 3.0), ("Hello (45.5 km)", 45.5), ("George St. (39.5 km)", 39.5), ("Salut (20.45 km)", 20.449999999999999), ("Bonjour (30 km)", 30.0), ("Hi (35 km)", 35.0)]
You can then sort this array by using the sort function. For example:
let sorted = stringsWithNumbers.sort {$0.number < $1.number}.map{$0.string} // sort, then ditch the distance information
print(sorted) // ["5th Avenue (3 km)", "Salut (20.45 km)", "Bonjour (30 km)", "Hi (35 km)", "George St. (39.5 km)", "Hello (45.5 km)"]
If you wish to keep the tuples of strings with doubles, you can remove the map at the end.
Assuming you're receiving this sort of input from some external source where you don't have to begin with the number as a separate field, you need to extract the component you want to sort by (the number) into some representation where you map the component you want to sort by to the original string (could be done also using a dictionary like in one of the other proposed solutions, then map your sorted number–string associated array to just the strings you wanted to get sorted as the third step.
My solution below is a bit verbose but it shows you how to extract the number out of the string, and takes care of bad input (the "Hi there", which doesn't include the numerical component at all, gets sorted at the end – you could just as well also easily filter it out given the distance component is modelled as an optional, and cases not following the pattern have this value as nil).
import Foundation
let arrayEntr = ["Hello (40 km)", "Salut (20 km)", "Bonjour (30 km)", "Hi (35 km)", "Hi there"]
let expr = try! NSRegularExpression(pattern: "\\((\\d+)", options: [])
typealias MatchTuple = (string:String, distance:Int?)
// 1. Extract the numbers out, and take into account possible bad input.
let matches = arrayEntr.map { str -> MatchTuple in
let range = expr.matchesInString(str, options: [], range: NSMakeRange(0, str.utf8.count)).first?.rangeAtIndex(1)
let match:String?
if let range = range {
match = (str as NSString).substringWithRange(range)
}
else {
match = nil
}
let distance:Int?
if let match = match {
distance = Int(match)
}
else {
distance = nil
}
return (string:str, distance:distance)
}
// 2. Sort the tuples of string / number combinations.
let sortedMatches = matches.sort { a, b in
if let aDist = a.distance, let bDist = b.distance {
return aDist < bDist
}
if a.distance == nil && b.distance == nil {
return a.string.compare(b.string) == .OrderedAscending
}
if a.distance != nil && b.distance == nil {
return true
}
return false
}
3. Map the string, number tuples into just the string.
print(sortedMatches.map { $0.string })
Create a dictionary like
let dictionary = [
"40" : "Hello (40 km)",
"20" : "Salut (20 km)",
"30" : "Bonjour (30 km)",
"35" : "Hi (35 km)",
]
and sort this dictionary as follow:
If you want only keys: let sortedKeys = Array(dictionary.keys).sorted(<) // ["20", "30", "35", "40"]
If you want sorted keys and values: let sortedKeysAndValues = sorted(dictionary) { $0.0 < $1.0 } // Resulted ArrayList [("20", "Salut (20 km)"), ("30", "Bonjour (30 km)"), ("35", "Hi (35 km)"), ("40", "Hello (40 km)")]
