I am trying to update my for loop for Swift 3 and I can't figure it out. I keep getting errors - swift

Question

This is my original function in Swift 2:
// check on winning combinations
func checkWinnerMove(){
for var i = 0; i<winningCombinations.count && !isWinner;i += 1 {
if gameState[winningCombinations[i][0]-1] == activePlayer &&
gameState[winningCombinations[i][1]-1] == activePlayer &&
gameState[winningCombinations[i][2]-1] == activePlayer{
isWinner = true;
}else{
isWinner = false;
}
}
}
I have changed it to this:
// check on winning combinations
func checkWinnerMove(){
for i in 0 ..< winningCombinations.count && !isWinner{
if gameState[winningCombinations[i][0]-1] == activePlayer &&
gameState[winningCombinations[i][1]-1] == activePlayer &&
gameState[winningCombinations[i][2]-1] == activePlayer{
isWinner = true;
}else{
isWinner = false;
}
}
}
But keep getting a error when I add the
&& !isWinner
statment in the for-in loop. The error I get is:
No '..<' candidates produce the expected contextual result type 'Bool'
Any suggestions? Thank You!

Answer 1

Instead of forcibly trying to rewrite your original C-style for loop, consider what you're trying to achieve and attempt to re-write it in "native" Swift from scratch. How about breaking out of your loop once your true condition is met, instead of keeping it in the loop signature? E.g.
for i in 1...5 {
print(i)
if i == 3 { break }
} // 1 2 3
Applied to your example
func checkWinnerMove()
isWinner = false
for i in 0 ..< winningCombinations.count {
if gameState[winningCombinations[i][0]-1] == activePlayer &&
gameState[winningCombinations[i][1]-1] == activePlayer &&
gameState[winningCombinations[i][2]-1] == activePlayer {
isWinner = true
break
}
}
}
The explicit by index access of the (unknown for us) gameState and winningCombinations sequences is quite "unswifty" w.r.t. in the dangers of runtime exceptions for indices out of range for the sequences. So bear in mind that there are safer ways to perform such access.
For future reference, consider reading How to create a Minimal, Complete, and Verifiable example: since we (the potential answerer's of your question) don't have access to/the full information regarding isWinner, winningCombinations, gameState or activePlayer, we can't verify your example. Also, since the question cover a concept, it could be boiled down to a more minimal form. (Welcome to StackOverflow!)