Check if array contains element in Swift 4 - arrays

Question

I am trying to check if array categories contain number 1 as Int since categories = [Int]() for example categories = {1, 2, 3, 4, 5}
I have tried the below code which gives me error Binary operator '==' cannot be applied to operands of type 'Any' and 'Int'
if categories.contains (where: {$0 == 1}) {
// 1 is found
}
also tried it without the where and brackets as below which gives me the same error
if categories.contains { $0 == 1 } {
// 1 is found
}
I tried using just the element as below which gives me error Missing argument label 'where:' in call
if categories.contains(1) {
// 1 is found
}
How can I do that?

Answer 1

It seems like your category array is of type Any
Ways to fix it
You can declare your array as an Int array
var categories: [Int]
OR
You can change the following piece of code
if categories.contains { $0 == 1 } {
// 1 is found
}
to
if categories.contains { ($0 as! Int) == 1 } {
// 1 is found
}
Note: This method might cause your app to crash if your category array has an element other than of type Int

Answer 2

it is working See my output in PlayGround
Code used:
var categories : [Int] = [0,1,2,3,4,5,6,7,8,9]
if categories.contains(5)
{
print("Yes it contains")
}
else
{
print("it do not")
}
and also This condition is working
if categories.contains (where: {$0 == 1}) {
print("yes")
}
see your Array Declaration I think there is main Issue
Declaration 1 :
var categories = [Int]()
categories = [0,1,2,3,4,5,6,7,8,9]
Declaration 2 :
var categories : [Int] = [0,1,2,3,4,5,6,7,8,9]

Answer 3

Regarding error message
Binary operator '==' cannot be applied to operands of type 'Any' and 'Int'
Your array is not an Int array instead it contains Any so it needs typecasting before comparision. Declaration of array is also wrong use [] instead of {}. And typecast object as an int ($0 as! Int) == 1 (I'm using force casting here because I know its an Int array).
There are many ways to check if array contains any element.
1> Just try to get the index of element with guard if index is nil means array doesn't contain the element. Although you didn't declare array in right way still I'm considering it a valid array.
let categories: [Int] = [1, 2, 3, 4, 5]
guard categories.index(of: 1) != nil else {
print("Doesn't Contain")
return
}
print("Contains")
2> Use contains method
if (categories.contains(1)) {
print("Contains")
}
else {
print("Doesn't Contain")
}
3> Not Recommended for this case But still you can get this
let result = categories.filter({$0 == 1})
if result.count == 0 {
print("Doesn't Contain")
}
else {
print("Contains")
}
filter returns an array of element which matches with condition. So that if there are multiple 1 in array so it will give you an array of all elements. And $0 describes the object while enumerating the array.
4> Not Recommended for this case
let contains = categories.contains(where: {$0 == 1})
if contains {
print("Contains")
}
else {
print("Doesn't Contain")
}

Answer 4

Thanks to your comments made me check the declaration of the array and the problem was that was declared as [Any] after I get it's value from the UserDefaults. I have checked and found the solution on How do I save an Int array in Swift using NSUserDefaults?
// old declaration
let categories = userDefaults.array(forKey:"categories") ?? [Int]()
// new correct declaration
var categories = [Int]()
if let temp = userDefaults.array(forKey:"categories") as? [Int] {
categories = temp
}