iosswifthex

Swift build hexadecimal from array (active/inactive states) of Int and get an integer form hexadecimal

Let say we can mark weekend day active or inactive. I need to use Integer to say system that I marked day active or inactive, to retrieve this integer I need to use array [1, 1, 1, 1, 1, 1, 1]. So if you see at this array all day of week marked as active and in Hexadecimal it's 0000007F.

If I use [0, 0, 0, 0, 0, 0, 1] this string it means Hexadecimal = 00000001. So my question is how to create Hexadecimal from array and then get form it an Integer. So in case with 0000007F it should be 127.

I assume that it should be something like that:

let array = [1, 1, 1, 1, 1, 1, 1] let hexadecimal = array.toHexadecimal let intNumber = hexadecimal.toInt

print(intNumber) // prints 127

Also I guess it can be for example an array with ints like [0, 1, 1, 1, 1, 0, 1] which means that Monday and from Wednesday till Saturday (including) are active days.

Solution

  • You can use reduce method to sum up your binary array (inspired at this answer) and use String(radix:) initializer to convert your integer to hexa string:

    Swift 3 • Xcode 8 or later

    let binaryArray =  [1, 1, 1, 1, 1, 1, 1]

let integerValue = binaryArray.reduce(0, {$0*2 + $1})
let hexaString = String(integerValue, radix: 16)  // "7f"