PHP: calculates the number of digits after the decimal point

This article provides two methods, one is to convert the decimal number into a string, and then use "." To intercept, remove the length of the. substring. Another method is to explain the N power of decimal * 10. For example, to the power of 10, the remainder is obtained for the power of 8, and then the remainder is continuously obtained for 10, until the result of 10 is not 0.

In comparison, the first method is much better. The reason is that, for example, when 1.000004 is at a very boundary or 0.99999, PHP processing may have problems and errors, resulting in different digits. The accuracy is hard to grasp, so we can use strings or strings to solve this boundary-related problem.

First

Private function _ getFloatLength ($ num) {$ count = 0; $ temp = explode ('. ', $ num); if (sizeof ($ temp)> 1) {$ decimal = end ($ temp); $ count = strlen ($ decimal );} return $ count ;}

Second

Function getfloatlength ($ a) {if ($ a-(int) $ a) <1E-9) {$ count = 0 ;}$ a = fmod (1E9 * $, 1E9); while ($ a % 10 = 0) {if ($ a = 0) break; $ a = $ a/10; $ count --;} return count ;}