Swift Bool Function return will never executed - swift

Question

I want to create a code which can determine whether the character is one of the symbols in my list.
var symbols = ["+","-"]
func issymbol(last:String ) -> Bool{
return true
for i in 0...(symbols.count){
if last == symbols[i]{
return false
}
}
}

Answer 1

You need to add return true at the end and it will execute if last == symbols[i]{ never met. So update your code as shown below:
func issymbol(last:String) -> Bool{
for i in 0...(symbols.count){
if last == symbols[i]{
return false
}
}
return true
}
issymbol(last: "+") //false
Or you can use contains property for that:
func issymbol(last:String) -> Bool{
return !symbols.contains(last)
}
issymbol(last: "+") // false
issymbol(last: "1") // true

Answer 2

No code execute after return keyword. so I update your code try this
var symbols = ["+","-"]
func issymbol(last:String ) -> Bool{
for value in symbols {
if last == value {
return true
}
}
return false
}

Answer 3

Functions only execute until they reach a return statement. Xcode detected that the rest of the code in that function won't be executed, because your function will always return after the first line. You probably meant something like this:
var symbols = ["+","-"]
func issymbol(last:String ) -> Bool{
for i in 0...(symbols.count){
if last == symbols[i]{
return false
}
}
return true
}
Because the return statement is after the for loop, the for loop can execute. This function will return true if the string you pass in is not in the symbols array.

Answer 4

There are a lot issues in this code.
The line return true returns immediately so the check won't be performed (the error message).
The line for i in 0...(symbols.count) will crash because the index starts at 0 and the last index is symbols.count - 1. Alternatively you can write for i in 0..<symbols.count.
The best syntax is not to write an index based loop:
for symbol in symbols { if last == symbol ...
If the item is found the code returns false rather than true.
The code doesn't return a Bool after the loop if the item was not found (will cause another error).
The correct code is
let symbols = ["+","-"]
func issymbol(last: String) -> Bool {
for i in 0...symbols.count - 1 {
if last == symbols[i] {
return true
}
}
return false
}
However this can be reduced to
func issymbol(last: String) -> Bool {
return symbols.contains(last)
}