Compare String against String Array

Question

I'm currently trying to determine the best way to compare a string value to an array of Strings. Here's the problem...

I'm building a converter between binary, decimal and hex values that share the same keypad. I want to check the input and depending on the mode, let it through or not (e.g. binary more only allows 1 and 0, decimal 0-9 and hex 0-F).

I can do this by saying:

if (digit == binaryDigits[0]) || (digit == binaryDigits[1]) {
// do something
}

but that's not very practical when it comes to the decimal and hex values.

Basically I would like a way to check a given String against all values within a String Array.

Is this what you need: How to check if an element is in an array ? — Martin R
– Martin R, Commented Jan 30, 2015 at 17:03

Christian · Accepted Answer · 2015-01-30 17:11:20Z

5

You can use the contains() method:

var strings = ["Test", "hi"]
if contains(strings , "hi") {
    println("Array contains string")
}

answered Jan 30, 2015 at 17:11

Christian

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Comments

AW5 · Accepted Answer · 2018-04-24 10:40:18Z

4

Use stringArray.contains(string)

Example:

let cast = ["Vivien", "Marlon", "Kim", "Karl"]
print(cast.contains("Marlon")) 
// Prints "true"
print(cast.contains("James"))  
// Prints "false"

Visit https://developer.apple.com/documentation/swift/array/2945493-contains

edited Apr 24, 2018 at 10:40

answered Apr 24, 2018 at 10:33

AW5

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3 Comments

SimonTheEngineer Over a year ago

Thanks, that's the same as what Christian suggested

AW5 Over a year ago

Not exactly... contains(array, string) did not work for me since it has been changed to array.contains(string)

SimonTheEngineer Over a year ago

Oh yeah I'm sorry, didn't notice that difference. I just saw 'contains' and assumed it was the same. Apologies... Marked yours as the answer as it's up-to-date

Echelon · Accepted Answer · 2015-01-30 17:11:53Z

0

This may not be the most elegant solution but it's clear and concise:-

func isValidHex( input: String ) -> Bool {
    let hset:NSCharacterSet = NSCharacterSet(charactersInString:"0123456789ABCDEF")
    return (countElements(input.stringByTrimmingCharactersInSet(hset)) == 0)
}

func isValidDecimal( input: String ) -> Bool {
    let hset:NSCharacterSet = NSCharacterSet(charactersInString:"0123456789")
    return (countElements(input.stringByTrimmingCharactersInSet(hset)) == 0)
}

func isValidBinary( input: String ) -> Bool {
    let hset:NSCharacterSet = NSCharacterSet(charactersInString:"01")
    return (countElements(input.stringByTrimmingCharactersInSet(hset)) == 0)
}

answered Jan 30, 2015 at 17:11

Echelon

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2 Comments

SimonTheEngineer Over a year ago

Thanks for the idea! I think I'll use the contains() method some others posted but thanks for a different way of doing it

Echelon Over a year ago

Think I misunderstood your question. I thought you wanted to validate if strings were binary, decimal or hex.

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