In Python, the round () function is used to round a numerical value. Its syntax is: round(number[, ndigits]), where number is the numerical value to be rounded and ndigits is the parameter to keep decimal places. If the ndigits parameter is not specified, it defaults to 0, that is, the value is rounded to the nearest integer. If ndigits is negative, it means rounding the value to the left of the decimal point. For example, the result of round( 12345, -3) is 12000. ?

In practical applications, the round () function is often used to print format values. For example, suppose we want to keep two decimal places of a numerical value, we can use the round () function to round it to two decimal places and then output it.

In addition to the normal rounding operation, the round () function can also be used to deal with some special cases. For example, due to the precision of floating-point numbers, some unexpected results may appear when comparing floating-point numbers. To solve this problem, you can use the round () function to round floating-point numbers to a specified precision and then compare them.

In addition, you can use the round () function to adjust the numerical value to meet some specific requirements. For example, to avoid extra zeros after the decimal point, you can use the round () function to round the value to the last non-zero digit after the decimal point.