Another approach :

NumberFormat format = NumberFormat.getCurrencyInstance();
format.setMaximumFractionDigits(0);
format.setCurrency(Currency.getInstance("EUR"));

format.format(1000000);

This way, it's displaying 1 000 000 € or 1,000,000 €, depending on device currency's display settings

use as follows:

private val currencyFormat = NumberFormat.getCurrencyInstance()

Pass the desired Locale to getCurrencyInstance():

val format = NumberFormat.getCurrencyInstance(Locale("es", "MX"))

"MX $3000.00".takeLastWhile { it != '$' }

is one of many ways.

val result = "[^\\d]+?(\\d+\\.?\\d*)".toRegex().find("MX $3000.00")
result?.groupValues?.last()

works too.

The problem is there's no way to tell whether you started with an Int or a Float. If you started with 3000, it formats as 3000.00 and if you started with 3000.45, it formats as 3000.45. The result will be a Float, and you can choose what to do with it.

For sake of completeness suppose you want to display a price in phone's current locale (correct decimal mark and thousand separator) but with a currency of your choice.

NumberFormat format = NumberFormat.getCurrencyInstance(Locale.getDefault());
format.setCurrency(Currency.getInstance("CZK"));
String result = format.format(1234567.89);

result would then hold these values:

• CZK1,234,567.89 with US locale
• 1 234 567,89 Kč with Czech locale

If you'd like to omit the decimal part for prices (show $199 instead of $199.00) call this before using the formatter:

format.setMinimumFractionDigits(0);

All options are listed in NumberFormat docs.