我怎样才能在非科学计数法中得到一个大数字？

Question

我刚试过

>>> 2.17 * 10**27
2.17e+27
>>> str(2.17 * 10**27)
'2.17e+27'
>>> "%i" % 2.17 * 10**27
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: cannot fit 'long' into an index-sized integer
>>> "%f" % 2.17 * 10**27
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: cannot fit 'long' into an index-sized integer
>>> "%l" % 2.17 * 10**27
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: incomplete format

现在我运行没主意了。我想得到

2170000000000000000000000000

如何打印这么大的数字？（我不在乎它是 Python 2.7+ 解决方案还是 Python 3.X 解决方案）

Answer 1

您的运算符优先级错误。您正在格式化 2.17，然后将其乘以一个长整数：

>>> r = "%f" % 2.17
>>> r
'2.170000'
>>> r * 10 ** 27
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: cannot fit 'long' into an index-sized integer

在乘法两边加上括号：

>>> "%f" % (2.17 * 10**27)
'2169999999999999971109634048.000000'

这是为字符串格式重载模数运算符的缺点之一；较新的 Format String syntax used by the str.format() method and the Format Specification Mini-Language it employs (and can be used with the format() function) 巧妙地避开了这个问题。对于这种情况，我会使用 format()：

>>> format(2.17 * 10**27, 'f')
'2169999999999999971109634048.000000'

我怎样才能在非科学计数法中得到一个大数字？

How can I get a big number in non-scientific notation?

python

formatting

number-formatting