为什么Python在前面有0时会改变整数的值？ [英] Why does Python change the value of an integer when there is a 0 in front of it?

问题描述

我实现了一个函数，将整数转换为字符串 intToStr（）（下面的代码）。

I implemented a function converting an integer number to its representation as a string intToStr() (code below).

为了测试，我传入了一些值并观察到意外的输出：

For testing I've passed in some values and observed an unexpected output:

print intToStr( 1223) # prints 1223 as expected
print intToStr(01223) # prints  659, surprisingly 

现在，我已经试图调试它，我传入的整数确实是 659 。

Now, I've tried to debug it, and the the integer I've passed in has indeed turned out to be 659.

为什么会发生这种情况？如何让python忽略整数字的前导零？

Why does this happen and how can I get python to ignore leading zeros of the integer literal?

这是我的函数的代码：

def intToStr(i):
    digits = '0123456789'
    if i == 0:
        return 0
    result = ""
    while i > 0:
        result = digits[i%10] + result
        i /= 10
    return result

推荐答案

正如其他人所说的那样是因为八进制数。但我强烈建议您将功能更改为：

As others have said that's because of octal numbers. But I strongly suggest you to change your function to:

>>> from functools import partial
>>> force_decimal = partial(int, base=10)
>>> force_decimal("01")
1
>>> force_decimal("0102301")
102301

这样你就明确强制转换为base 10.并且int不会为你推断它。

This way you will explicitly force the conversion to base 10. And int wont be inferring it for you.

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