指数位数

没有办法控制，最好的办法就是为此编写一个函数，例如

def eformat(f, prec, exp_digits):    s = "%.*e"%(prec, f)    mantissa, exp = s.split('e')    # add 1 to digits as 1 is taken by sign +/-    return "%se%+0*d"%(mantissa, exp_digits+1, int(exp))print eformat(0.0000870927939438012, 14, 3)print eformat(1.0000870927939438012e5, 14, 3)print eformat(1.1e123, 4, 4)print eformat(1.1e-123, 4, 4)

输出：

8.70927939438012e-0051.00008709279394e+0051.1000e+01231.1000e-0123