如何扩展长数字(以 e+## 结尾)以扩展形式显示? [英] How do I expand a long number (ending in e+##) to show in expanded form?

问题描述

所以，这可能是一个简单的问题，但我在任何地方都找不到答案.

例如我有一个简单的程序，我想像这样将 a 除以 b:

def main():a = 12345678900000000b = 1.25答案 = (a/b)打印(答案)主要的()

这个特定的例子将导致 9.87654312e+15.如何让 Python 忽略简化我的数字而只给我整数?

提前致谢，抱歉，如果它真的很基础，我不会问我是否可以通过 Google 找到它.

解决方案

您看到浮点数的默认 str() 转换在起作用.您可以通过明确格式化数字来选择不同的转换.

format() 函数可以为您做到这一点:

<预><代码>>>>n = 9.87654312e+15>>>格式(n，'f')'9876543120000000.000000'

有关更多选项，请参阅格式规范迷你语言文档.'f' 格式只是以下格式之一:

<块引用>

固定点.将数字显示为定点数.默认精度为 6.

默认精度导致.000000 小数点后六位数字；你可以使用 .

f 来改变它:

<预><代码>>>>格式(n，'.1f')'9876543120000000.0'

但要考虑到小数会四舍五入以符合要求的精度.

g 格式在使用指数 (e) 和 f 符号之间切换，取决于数字的大小，但不会如果数字是整数，则包括小数；你可以在 'g' 中使用一个非常大的精度来避免完全打印小数:

<预><代码>>>>格式(n，'.53g')'9876543120000000'

明确地说，str(n) 等同于 format(n, '.12g'), repr(n)是 format(n, '.17g');当指数大于精度时，两者都可以使用指数格式.

So, this may be a simple question but I'm having some trouble finding the answer anywhere.

Take for example I have a simple program where I want to divide a by b like so:

def main():
    a = 12345678900000000
    b = 1.25

    answer = (a / b)
    print(answer)
main()

This particular example would result in 9.87654312e+15. How do I get Python to ignore simplifying my number and just give me the whole number?

Thanks in advance, sorry if it's really basic, I wouldn't have asked if I could have found it through Google.

解决方案

You are seeing the default str() conversion for floating point numbers at work. You can pick a different conversion by formatting the number explicitly.

The format() function can do this for you:

>>> n = 9.87654312e+15
>>> format(n, 'f')
'9876543120000000.000000'

See the Format Specification Mini-Language documentation for more options. The 'f' format is but one of several:

Fixed point. Displays the number as a fixed-point number. The default precision is 6.

The default precision resulting in the .000000 six digits after the decimal point; you can alter this by using .<precision>f instead:

>>> format(n, '.1f')
'9876543120000000.0'

but take into account that decimals are rounded to fit the requested precision.

The g format switches between using exponents (e) and f notation, depending on the size of the number, but won't include decimals if the number is whole; you could use a very large precision with 'g' to avoid printing decimals altogether:

>>> format(n, '.53g')
'9876543120000000'

To be explicit, str(n) is the same as format(n, '.12g'), repr(n) is format(n, '.17g'); both can use the exponent format when the exponent is larger than the precision.

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