filters.py 文件源码

def do_round(value, precision=0, method='common'):
    """Round the number to a given precision. The first
    parameter specifies the precision (default is ``0``), the
    second the rounding method:

    - ``'common'`` rounds either up or down
    - ``'ceil'`` always rounds up
    - ``'floor'`` always rounds down

    If you don't specify a method ``'common'`` is used.

    .. sourcecode:: jinja

        {{ 42.55|round }}
            -> 43.0
        {{ 42.55|round(1, 'floor') }}
            -> 42.5

    Note that even if rounded to 0 precision, a float is returned.  If
    you need a real integer, pipe it through `int`:

    .. sourcecode:: jinja

        {{ 42.55|round|int }}
            -> 43
    """
    if not method in ('common', 'ceil', 'floor'):
        raise FilterArgumentError('method must be common, ceil or floor')
    if method == 'common':
        return round(value, precision)
    func = getattr(math, method)
    return func(value * (10 ** precision)) / (10 ** precision)