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kotlinlang

Hello ,
how to write this function is best way ?
```fun String?.trimTrailingZeros(): String? {
    if (isNullOrEmpty() || this!!.indexOf(".") &lt; 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

anyway, given that,
```fun String.trimTrailingZeros(): String =
    if ('.' in this) trimEnd('0').trimEnd('.') else this```
would be a straightforward translation without using regex

<@UJQB4DJF7> 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() --&gt; 1```
but these cases don’t work as expected:
```"1.1000".trimTrailingZeros() --&gt; 1.1
"1.10200".trimTrailingZeros() --&gt; 1.102```
is this correct?

that's what the original function returns too

never mind, I misunderstood the requirement when reading the code :smile:

Or just `replace("[.]?0*$".toRegex(), "")`  (although still need to check a period exists before calling this).

Note: the `trimEnd()` function will remove all trailing characters and so is a little different from the OP’s second regex which only replaces last period.

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>

of course it has to fit in Double etc etc