TypeError unhashable type 'list'

Question

I'm attempting a binary search problem from leetcode and this is my code below (ignore if it's not the proper implementation, i'd like to figure it out myself):

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        middle = int(len(nums)/2)
        ind = -1
        
        if(nums[middle] == target):
            return ind
        elif (nums[middle] > target):
            ind = middle
            nums = nums[:middle-1]
            print(nums)
            search(nums, target)
        else:
            ind = middle
            nums = nums[middle:len(nums)-1]
            print(nums)
            search(nums, target)

I'm trying to get my code to recurse using a slice of a list, but I keep getting this error:

TypeError: unhashable type: 'list'
return _cache[type(pattern), pattern, flags]
Line 293 in _compile (/usr/lib/python3.10/re.py)
    return _compile(pattern, flags).search(string)
Line 200 in search (/usr/lib/python3.10/re.py)
    search(nums, target)
Line 17 in search (Solution.py)
    ret = Solution().search(param_1, param_2)
Line 42 in _driver (Solution.py)
    _driver()
Line 53 in <module> (Solution.py)

I don't understand what this means in regards to search(nums,targets).

Answer 1

Your code, somewhere, is doing from re import search (or, shudders, from re import *) at global scope. You then fail to properly invoke search on self, so it finds the re module function and calls that instead. As a bonus error, you're not returning the values from your recursive calls, so any time you recurse you end up returning None. The fixes are pretty simple at least, just change:

search(nums, target)

to:

return self.search(nums, target)

invoking the correct search method on self, and returning what it returns. The fix must be made in both places you're making the recursive call.