python - variable number of digit in format string

Question

Which is a clean way to write this formatting function:

def percent(value,digits=0):
    return ('{0:.%d%%}' % digits).format(value)

>>> percent(0.1565)
'16%'

>>> percent(0.1565,2)
'15.65%'

the problem is formatting a number with a given number of digits, I don't like to use both '%' operator and format method.

Answer 1

I like this one:

'{0:.{1}%}'.format(value, digits)

Test:

>> '{0:.{1}%}'.format(0.1565, 0)
'16%'
>> '{0:.{1}%}'.format(0.1565, 2)
'15.65%'