Swift: Cannot assign value of type 'String.CharacterView.index' to type 'Int' - swift

Question

Does anyone know why I get the following error when I run my code below?
Error: Cannot assign value of type 'String.CharacterView.index' to type 'Int'
var problem = "find the longest word in the problem description"
var last = problem.characters.last
let lastIndex = problem.characters.endIndex;
print(last);
var words:[String] = [String]();
var word:String = "";
var lastCheck:Int = 0;
for i in problem.characters{
lastCheck = lastCheck + 1
if i != " "{
word = word + String(i)
}
else if lastCheck = lastIndex{
words.append(word);
}
else if i == " "{
words.append(word)
word = ""
}
}
print(words)
UPDATE
I have tried changing the let lastIndex to var lastIndex but no luck

Answer 1

You can't compare lastCheck (an Int) and lastIndex (an Index).
You have to convert it:
var problem = "find the longest word in the problem description"
var last = problem.characters.last
let lastIndex = problem.characters.endIndex;
print(last);
var words:[String] = [String]();
var word:String = "";
var lastCheck:Int = 0;
for i in problem.characters{
lastCheck = lastCheck + 1
let lastIndexInt = problem.characters.startIndex.distanceTo(end: lastIndex) // new
if i != " "{
word = word + String(i)
}
else if lastCheck = lastIndex{
words.append(word);
}
else if i == " "{
words.append(word)
word = ""
}
}
print(words)

Answer 2

Here's a simpler solution to your problem:
let input = "find the longest word in the problem description";
let longest = input
.characters //get the input characters
.split(separator:" ", //split by spaces
maxSplits: 1000, //max number of splits
omittingEmptySubsequences: true) //omit "" splits
.map(String.init) //make new strings from the characters
.max{$0.characters.count < $1.characters.count} //get longest length word
print(longest)
Thanks to originaluser2

Answer 3

String.CharacterView.Index is a struct but not Int. So you cannot assign a Int to your String.CharacterView.Index variable. It's normal.
You have to convert to Int as #Amomchilov's answer, or use Index :
...
var lastCheck:String.CharacterView.Index = problem.startIndex
for i in problem.characters {
lastCheck = lastCheck.advancedBy(1)
...
}
Anyway, in order to find the longest word of a phrase, you can use builtIn function of Swift to get all words then compare their length.
For example:
let str = "find the longest word in the problem description"
var longestWord : String?
str.enumerateSubstringsInRange(str.startIndex..<str.endIndex, options:.ByWords) {
(substring, substringRange, enclosingRange, value) in
if let _subString = substring {
if longestWord == nil || longestWord!.characters.count < _subString.characters.count {
longestWord = _subString
}
}
}

Answer 4

Easy way to get all the words in sentence
var problem = "find the longest word in the problem description"
problem.enumerateSubstrings(in: (problem.range(of: problem))!, options: NSString.EnumerationOptions.byWords, { (substring, substringRange, enclosingRange, stop) -> () in
print(substring)
})
Easy way to get longest word in sentence
var longestWord = ""
problem.enumerateSubstrings(in: (problem.range(of: problem))!, options: NSString.EnumerationOptions.byWords, { (substring, substringRange, enclosingRange, stop) -> () in
if longestWord.characters.count < substring?.characters.count{
longestWord = substring!
}
})
print(longestWord)
Note:Code with reference to Swift 3.For lower version of there will be some syntax changes.Let me know if you need the same for lower versions.