Decorator that truncates all decimal arguments of wrapped function to n digits

truncate_args.py

def truncate(f, n):
    '''Truncates/pads a float f to n decimal places without rounding'''
    s = '{}'.format(f)
    if 'e' in s or 'E' in s:
        return '{0:.{1}f}'.format(f, n)
    i, p, d = s.partition('.')
    return float('.'.join([i, (d+'0'*n)[:n]]))

def truncate_args(digits):
    def decorator(func):
        def wrapper(*args):
            args = (truncate(x, digits) for x in args)
            return func(*args)
        return wrapper
    return decorator