1. 使用输入值初始化列表

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nums = [] rows = eval(input("请输入行数：")) columns = eval(input("请输入列数：")) for row in range(rows):   nums.append([])   for column in range(columns):     num = eval(input("请输入数字："))     nums[row].append(num) print(nums)

2. 使用随机数初始化列表

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import random numsList = [] nums = random.randint(0, 9) rows = random.randint(3, 6) columns = random.randint(3, 6) for row in range(rows):   numsList.append([])   for column in range(columns):     num = random.randint(0, 9)     numsList[row].append(num) print(numsList)

3. 对所有的元素求和

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nums = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [3, 4, 7]] total = 0 for i in nums:   for j in i:     total += j print(total)

4. 按列求和

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nums = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [3, 4, 7]] total = 0 for column in range(len(nums[0])):   # print("column = ",column)   for i in range(len(nums)):     total += nums[i][column]   print(total)