Code:
<?php
$btc = 0.00023500;
echo number_format($btc, 8, '.', ',');
echo intval(($btc*100000000))/100000000;
echo floor(($btc*100000000))/100000000;
?>
1. number_format = output: 0.00023500
The 8 are the decimal places, the dot is the "decimal separator" and the comma is the "thousands separator".
2. intval = output: 0.000235
8 decimal places are output, unless the value is zero, then only the actual decimal places are given.
3. floor = output: 0.000235
8 decimal places are output, unless the value is zero, then only the actual decimal places are given.
* There are more spellings. But these are easy to derive from the understanding.