all Python 3Arithmetic & operatorsfunction

round()

numbers

Built-in rounding function. With one argument it returns an int; with ndigits it rounds to that many decimal places. It uses banker's rounding (to the nearest even).

Syntax

round(number[, ndigits])

round(2.675, 2) yields 2.67, and banker's rounding is not the culprit — the binary float actually stored is slightly below the decimal 2.675. For money use decimal.Decimal with quantize(). Also note that round(x) without ndigits returns an int while round(x, 0) returns a float (2.0), so "round to an integer" and "round to zero digits" are different requests.

Examples

print(round(3.7))  # → 4
print(round(3.14159, 2))  # → 3.14
print(round(2.5))  # → 2 (банковское округление к чётному)
print(round(3.5))  # → 4 (банковское округление к чётному)
print(round(12345, -2))  # → 12300 (до сотен)
print(round(0.1 + 0.2, 10))  # → 0.3 (компенсация float погрешности)

See also

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