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](http://stackoverflow.com/questions/24102024/how-to-check-if-an-element-is-in-an-array) ? — Martin R, Jan 30 '15 at 17:03

score 5 · Answer 1 · answered Jan 30 '15 at 17:11

5

You can use the contains() method:

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

answered Jan 30 '15 at 17:11

Christian

22,585
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80
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AW5 · Accepted Answer · 2018-04-24T10:40:18.937

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 '18 at 10:40

answered Apr 24 '18 at 10:33

AW5

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3
12

Thanks, that's the same as what Christian suggested – SimonTheEngineer Apr 25 '18 at 12:40
Not exactly... contains(array, string) did not work for me since it has been changed to array.contains(string) – AW5 Apr 26 '18 at 09:32
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 – SimonTheEngineer Apr 26 '18 at 16:58

score 0 · Answer 3 · answered Jan 30 '15 at 17:11

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)
}

Thanks for the idea! I think I'll use the contains() method some others posted but thanks for a different way of doing it — SimonTheEngineer, Jan 30 '15 at 21:04
Think I misunderstood your question. I thought you wanted to validate if strings were binary, decimal or hex. — Echelon, Feb 02 '15 at 17:25

Compare String against String Array

3 Answers3