CODEWITHSUNDEEP
swiftwhere-clause
user1094081
user1094081

Reputation:

Verify multiple conditions with contains(where:)

With this code I enable a button if any form value is not nil:

myButton.isEnabled = !myForm.values.contains(where: { $0 == nil })

Is there any way to add multiple checks? I want to enable my button:

(that is, the value should NOT be nil and should NOT be outside the range 0.0 - 2.0)

Can I still use contains(where:) to do it?

MyForm is a dictionary like this one:

 ["oct": nil, 
     "jan": Optional(3666.0), 
     "nov": nil, 
     "apr": nil, 
     "sep": nil, 
     "feb": nil, 
     "jul": nil, 
     "mar": nil, 
     "dec": nil, 
     "may": nil, 
     "jun": nil, 
     "aug": nil]

(strange enough, due to the behavior of a 3rd party library, it accepts nil values)

Upvotes: 0

Views: 135

Answers (2)

vadian
vadian

Reputation: 285180

Yes, you can. If you want to enable the button if there is at least one Double value in range 0.0..<2.0 you don't need to call values. You can call contains on the dictionary directly. The where keyword is syntactic sugar and can be omitted when using trailing closure syntax.

The code uses the pattern matching operator to check the range.

myButton.isEnabled = myForm.contains { (_, value) in
    guard let value = value as? Double else { return false }
    return 0.0..<2.0 ~= value
}

If you want to enable the button if all values are Double in the given range you have to check inverted

myButton.isEnabled = !myForm.contains { (_, value) in
    guard let value = value as? Double else { return true }
    return !(0.0..<2.0 ~= value)
}

Upvotes: 1

Taras Chernyshenko
Taras Chernyshenko

Reputation: 2829

You can do it just by filtering all values like this:

myButton.isEnabled = !myForm.values.filter { 
    if let value = $0 { return value.field > 0.0 && value.field < 2.0 }
    return false 
}.count > 0

contains function is not appropriate solution in your case, because it should be used when you need to check if array contain some specific element. But in your case you need to check if values is in specific range. It is possible to use contains function but it is not correct way

Upvotes: 1

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