Insert or split string at uppercase letters objective-c - objective-c

Question

What would be the most efficient way to convert a string like "ThisStringIsJoined" to "This String Is Joined" in objective-c?
I receive strings like this from a web service thats out of my control and I would like to present the data to the user, so I would just like to tidy it up a bit by adding spaces infront of each uppercase word. The strings are always formatted with each word beginning in an uppercase letter.
I'm quite new to objective-c so cant really figure this one out.
Thanks

Answer 1

One way of achieving this is as follows:
NSString *string = #"ThisStringIsJoined";
NSRegularExpression *regexp = [NSRegularExpression
regularExpressionWithPattern:#"([a-z])([A-Z])"
options:0
error:NULL];
NSString *newString = [regexp
stringByReplacingMatchesInString:string
options:0
range:NSMakeRange(0, string.length)
withTemplate:#"$1 $2"];
NSLog(#"Changed '%#' -> '%#'", string, newString);
The output in this case would be:
'ThisStringIsJoined' -> 'This String Is Joined'
You might want to tweak the regular expression to you own needs. You might want to make this into a category on NSString.

Answer 2

NSRegularExpressions are the way to go, but as trivia, NSCharacterSet can also be useful:
- (NSString *)splitString:(NSString *)inputString {
int index = 1;
NSMutableString* mutableInputString = [NSMutableString stringWithString:inputString];
while (index < mutableInputString.length) {
if ([[NSCharacterSet uppercaseLetterCharacterSet] characterIsMember:[mutableInputString characterAtIndex:index]]) {
[mutableInputString insertString:#" " atIndex:index];
index++;
}
index++;
}
return [NSString stringWithString:mutableInputString];
}

Answer 3

Here's a category on NSString that will do what you want. This will handle non-ASCII letters. It will also split "IDidAGoodThing" properly.
#implementation NSString (SeparateCapitalizedWords)
-(NSString*)stringBySeparatingCapitalizedWords
{
static NSRegularExpression * __regex ;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSError * error = nil ;
__regex = [ NSRegularExpression regularExpressionWithPattern:#"[\\p{Uppercase Letter}]" options:0 error:&error ] ;
if ( error ) { #throw error ; }
});
NSString * result = [ __regex stringByReplacingMatchesInString:self options:0 range:(NSRange){ 1, self.length - 1 } withTemplate:#" $0" ] ;
return result ;
}
#end

Answer 4

Here is Swift Code (objective c code by webstersx), Thanks !
var str: NSMutableString = "iLoveSwiftCode"
var str2: NSMutableString = NSMutableString()
for var i:NSInteger = 0 ; i < str.length ; i++ {
var ch:NSString = str.substringWithRange(NSMakeRange(i, 1))
if(ch .rangeOfCharacterFromSet(NSCharacterSet.uppercaseLetterCharacterSet()).location != NSNotFound) {
str2 .appendString(" ")
}
str2 .appendString(ch)
}
println("\(str2.capitalizedString)")
}
Output : I Love Swift Code

Answer 5

For anyone who came here looking for the similar question answered in Swift:
Perhaps a cleaner (adding to Sankalp's answer), and more 'Swifty' approach:
func addSpaces(to givenString: String) -> String{
var string = givenString
//indexOffset is needed because each time replaceSubrange is called, the resulting count is incremented by one (owing to the fact that a space is added to every capitalised letter)
var indexOffset = 0
for (index, character) in string.characters.enumerated(){
let stringCharacter = String(character)
//Evaluates to true if the character is a capital letter
if stringCharacter.lowercased() != stringCharacter{
guard index != 0 else { continue } //"ILoveSwift" should not turn into " I Love Swift"
let stringIndex = string.index(string.startIndex, offsetBy: index + indexOffset)
let endStringIndex = string.index(string.startIndex, offsetBy: index + 1 + indexOffset)
let range = stringIndex..<endStringIndex
indexOffset += 1
string.replaceSubrange(range, with: " \(stringCharacter)")
}
}
return string
}
You call the function like so:
var string = "iLoveSwiftCode"
addSpaces(to: string)
//Result: string = "i Love Swift Code"
Alternatively, if you prefer extensions:
extension String{
mutating func seperatedWithSpaces(){
//indexOffset is needed because each time replaceSubrange is called, the resulting count is incremented by one (owing to the fact that a space is added to every capitalised letter)
var indexOffset = 0
for (index, character) in characters.enumerated(){
let stringCharacter = String(character)
if stringCharacter.lowercased() != stringCharacter{
guard index != 0 else { continue } //"ILoveSwift" should not turn into " I Love Swift"
let stringIndex = self.index(self.startIndex, offsetBy: index + indexOffset)
let endStringIndex = self.index(self.startIndex, offsetBy: index + 1 + indexOffset)
let range = stringIndex..<endStringIndex
indexOffset += 1
self.replaceSubrange(range, with: " \(stringCharacter)")
}
}
}
}
Call the method from a string:
var string = "iLoveSwiftCode"
string.seperatedWithSpaces()
//Result: string = "i Love Swift Code"

Answer 6

You could try making a new string that is a lowercase copy of the original string. Then compare the two strings and insert spaces wherever the characters are different.
Use the NSString method to turn to lowercase.
- (NSString *)lowercaseString