Hello , how to write this function is best way ?

fun String?.trimTrailingZeros(): String? {
    if (isNullOrEmpty() || this!!.indexOf(".") < 0) return this
    return replace("0*$".toRegex(), "").replace("\\.$".toRegex(), "")
}

IMO it would be better to define it on

String

instead of

String?

. it returns null iff the receiver is null, so instead of doing that, just push the safe call to the consumers, e.g.

nullable?.trimTrailingZeros()

. if the receiver is non-nullable, this will ensure the result is also non-nullable

Ahh nice thanks 🙂

@ephemient very cool solution but I suspect it won’t always work. For example, this is what the OP wanted and it works:

"1.000".trimTrailingZeros() --> 1

but these cases don’t work as expected:

"1.1000".trimTrailingZeros() --> 1.1
"1.10200".trimTrailingZeros() --> 1.102

is this correct?

that's what the original function returns too

Oh I see maybe I got it wrong sorry…

why wouldn't it be correct?

never mind, I misunderstood the requirement when reading the code 😄

Or just

replace("[.]?0*$".toRegex(), "")

(although still need to check a period exists before calling this).

if there are multiple

.

in a row, yeah. that's actually easy to resolve if it is an issue though,

trimEnd('0').removeSuffix(".")

if they are numbers you could do a .toDouble().toString() as in: https://pl.kotl.in/An1Dc6M3Q