想对一个列表进行排序，比较规则如下：
'12'+'121' = '12121' > '12112' = '121' + '12'，
所以 12 > 121
这是我写的代码：
nums = [12, 121]
print sorted(nums, cmp=lambda x, y: int(str(x) + str(y)) > int(str(y) + str(x)))
输出为：[12, 121]，而我想要的是[121, 12]。不知道问题出在哪。。。
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Supplement 1 · May 9, 2015
已解决，背景见
https://leetcode.com/problems/largest-number/
http://v2ex.com/t/189719
def largestNumber(self, nums):
return str(int(''.join(sorted(map(str, nums), cmp=lambda x, y: int(x + y) - int(y + x), reverse=True))))
https://leetcode.com/problems/largest-number/
http://v2ex.com/t/189719
def largestNumber(self, nums):
return str(int(''.join(sorted(map(str, nums), cmp=lambda x, y: int(x + y) - int(y + x), reverse=True))))
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2
Valyrian May 9, 2015
cmp specifies a custom comparison function of two arguments (iterable elements) which should return a negative, zero or positive number depending on whether the first argument is considered smaller than, equal to, or larger than the second argument: cmp=lambda x,y: cmp(x.lower(), y.lower()). The default value is None.
你的cmp返回的是True/False，他要的是数字。另外你的符号好像也反了。可以试下以下任意一个： ``` cmp=lambda x, y: cmp(int(str(y) + str(x)), int(str(x) + str(y))) cmp=lambda x, y: int(str(y) + str(x)) - int(str(x) + str(y)) ``` 顺便，这个比较的逻辑有什么含义么，完全无法理解。。 |
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4
9hills May 9, 2015
cmp=lambda x, y: int(x + y) - int(y + x) 这个很赞。。
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5
C0VN May 9, 2015
sorted 中 cmp参数的用法都没有搞清楚
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