如何将列表的所有元素相乘以最终答案Python numpy无法正常工作

Question

Sorry about this. I'm new to Python and am doing a leetcode problem and I am currently trying to multiply all the numbers in the list together to get a final result. Here is my code:

import numpy 

class Solution:
    def productExceptSelf(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        arr = []

        for i in range(len(nums)):
            temp = nums[:i] + nums[i + 1 : len(nums)]
            result = numpy.prod(temp)
            arr.append(result)
        return arr

However I get this error:

Line 56: Exception: Type <class 'numpy.int64'>: Not implemented

Is there any other way to multiply all the elements in a list and storing in a value.

Answer 1

Try casting the numbers back into an integer:

return list(map(int, arr))

Or alternatively:

arr.append(int(result))

Answer 2

This is what I've ran in Spyder 3.5:

import numpy

class Solution:
def productExceptSelf(self, nums):
    """
    :type nums: List[int]
    :rtype: List[int]
    """
    arr = []

    for i in range(len(nums)):
        temp = nums[:i] + nums[i+1 : len(nums)]
        result = numpy.prod(temp)
        arr.append(result)
    return arr

a = [1, 2, 3, 4, 5, 6, 7]
solutionObject = Solution()
pES = solutionObject.productExceptSelf(a)
print(pES)

This is the output I've got:

[5040, 2520, 1680, 1260, 1008, 840, 720]

The code works perfectly fine with Spyder.

Answer 3

Similar to @Pranav's answer I ran your code with a random generated list and it worked successfully. Note that when the list exceeds 37 items then numpy.prod() will begin to fail and return 0 as the calculation has now exceeded the data type limit size. You can get pretty big pretty quickly using numpy.prod(). Looking at the error double check your list items are integers or floats.

import numpy 
import random

class Solution:
    def productExceptSelf(self, nums):
        """
        :type nums: List[int]
        :rtype: List[int]
        """
        arr = []

        for i in range(len(nums)):
            temp = nums[:i] + nums[i + 1 : len(nums)]
            result = numpy.prod(temp)
            arr.append(result)
        return arr

x = random.sample(range(0,100), 37)
answer = Solution()
product = answer.productExceptSelf(x)
print(product)

Could you provide us with the list that you are using when testing the function? That will help with reproducing your error.