CODEWITHSUNDEEP
arraysswiftstring
SomeGuyFortune
SomeGuyFortune

Reputation: 1056

Filter out null character strings from string array

I receive a json array of strings from an external source and some of my string look like 

"\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x00"

I would like to filter out all strings that only contain these null values. I've tried this 

arr = arr.filter { (str: String) -> Bool in
            let invalid = String(data: Data.init(count: str.count), encoding: String.Encoding.utf8)
            print(str)

            return str == invalid
        }

Since these are all null terminators, i decided to create a null string of the same length as str but only containing null terminators and compare them.

But this doesn't work. Any help will be appreciated.

Upvotes: 1

Views: 342

Answers (1)

Sweeper
Sweeper

Reputation: 273115

I don't think those are null terminators because the backslashes are escaped. Those are just the four character sequence \x00 repeated multiple times.

To match such a pattern, you can use regular expressions:

let regex = try! NSRegularExpression(pattern: "^(?:\\\\x00)+$", options: [])
let string = "\\x00\\x00\\x00\\x00\\x00"
// the below will evaluate to true if the string is full of \x00
regex.firstMatch(in: string, options: [], range: NSRange(location: 0, length: string.count)) != nil

Upvotes: 2

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