Kotlin has an excellent feature called string templates.

val i = 10 
val s = "i = $i" // evaluates to "i = 10"

But is it possible to have any formatting in the templates? For example I would like to format Double in string templates in kotlin, at least to set a number of digits after a decimal separator:

val pi = 3.14159265358979323
val s = "pi = $pi??" // How to make it "pi = 3.14"?


Unfortunately, there’s no built-in support for formatting in string templates yet, as a workaround, you can use something like:

"pi = ${pi.format(2)}"

the .format(n) function you’d need to define yourself as

fun Double.format(digits: Int) = java.lang.String.format("%.${digits}f", this)