Just wanted to see if anyone knows of an idiomatic way of adding a

,

between strings in a string builder. I know

joinToString

exists and it works great for arrays, but I basically want the same functionality for a string builder. Here's what I'm currently doing (no commas yet):

topic.data.forEach {
                    myBuilder.append("${it.city} ${it.status}")
                }
            }

Maybe I'm missing something basic. Thanks

Is using a

StringBuilder

a fixed necessity? If not you could for example do

topic.data.joinToString(',') { "${it.city} ${it.status}" }

IIRC you can also pass a

StringBuilder

to

joinTo

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/join-to.html

Ah, yes, you are right,

StringBuilder

is

Appendable

. So then it would be

topic.data.joinTo(myBuilder, ",") { "${it.city} ${it.status}" }

.

@nanodeath Hm. But I would need to make an empty array first and then call myEmptyArray.joinTo(myStringBuilder, ...).

I don't love that the city + status string generation is itself likely using a string builder, but I don't think there's much you can do about that without like...building up an arraylist by hand, and that's just not worth it.

@Vampire string builder isn't a fixed necessity. I guess I can just use your join to string suggesstion to. It's just muscle memory to use string builder when building strings. 😄 I'm sure it's a micro optimization now, but I wonder if there's any difference.

readability wise, probably

Anyone have any preference/idiomatic thoughts on topic.data.joinToString(',') { "${it.city} ${it.status}" } vs topic.data.joinTo(myBuilder, ",") { "${it.city} ${it.status}" }

Bad muscle memory then, should have

StringJoiner

in it 😄

I'd use

joinToString

if you don't already have and need a builder

Thanks everyone. Appreciate your time and experience.