How to convert Array<_Element> to array literal

Question

I want to use an array throughout my view controller so I declare it up top. However, I want populate this array with string elements. There is an easy way to do this with one line. I'm trying not to use a for loop.

var stringArray = [String]()
...
stringArray = Array(reversedWord.characters)

What is is not letting me do is convert Array<_elements> to an array literal.

It's not very clear what you're asking. Are you looking for stringArray = reversedWord.characters.map { String($0) }? — Eric Aya
– Eric Aya, Commented Jun 8, 2016 at 15:03
I'm looking to populate a string with characters. However, I do not know what to declare my initial array as. — paralaxbison
– paralaxbison, Commented Jun 8, 2016 at 15:14
Oh, in this case: var charArray = [Character](), then you will be able to do charArray = Array(reversedWord.characters). — Eric Aya
– Eric Aya, Commented Jun 8, 2016 at 15:15
Just another question, how do you convert a [Character] to a [String] — paralaxbison
– paralaxbison, Commented Jun 8, 2016 at 15:21
I've made an answer from my comments, and answered your last question. — Eric Aya
– Eric Aya, Commented Jun 8, 2016 at 15:26

Eric Aya · Accepted Answer · 2016-06-21 21:02:05Z

1

Your issue is that although there can be a String of one character, a single character is actually of type Character.

So when you declare an array of Strings, you can't populate this array later with Characters.

So, make an array of Character types from the beginning:

var charArray = [Character]()

This way, when you'll split a String into characters, you'll be able to add these characters to the array:

charArray += Array(reversedWord.characters)

And to convert an array of Character to an array of String, you can use map and the String() initializer:

let stringArray = charArray.map { String($0) }

Here, stringArray will be of type [String].

edited Jun 21, 2016 at 21:02

answered Jun 8, 2016 at 15:26

Eric Aya

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5 Comments

Alexander Over a year ago

You don't need the first ` = [Character]()` part. You're making an empty array only to almost instantly replace it with a new onw

Eric Aya Over a year ago

@AMomchilov I know. I was just imitating OP's example. But this is a good point, I'm making an edit. Thanks.

Eric Aya Over a year ago

@AMomchilov Actually, no, no edit: I did this on purpose. Read the beginning of OP's question: I want to use an array throughout my view controller so I declare it up top. But I fixed a typo (was = instead of += or append). :)

Alexander Over a year ago

Yes, that would just be an instance variable. You're clobbering it anyway everytime you reassign to it. I think OP was just using that array to let the compiler infer the type of charArray. It just needs a type annotation instead.

Eric Aya Over a year ago

Ok, there was a typo I just fixed, I just replaced = with += because that was my original intent (I explain ...able to add... to OP). No clobbering anymore. And no, I won't write just a type annotation here, because I think OP actually uses the array before this. Anyway: implementation detail related to OP's example, and doesn't contradict the explanation about Character != String, which is the heart of the answer: when you declare an array of Strings, you can't populate this array later with Characters. I think this is clear enough.

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