Question

现在我有元组列表，如下所示：

[(78, -32), (54, -32), (30, -32), (30, -8), (30, 16), (30, 40), (30, 64), (6, 64), (-18, 64), (-42, 64), (-66, 64), (-66, 88), (-90, 88), (-114, 88)]

我当前的代码如下：

i = 13 # Let i start at index 13
tech = [] # Define list
while (x, y) != (start_x, start_y): # while loop to iterate through all the coordinates until the path has been found
    tech.append(solution[x,y]) # Appends the coordinates to tech list
    x, y = solution[x, y] # get x and y coordinates

for i in tech: # Loop thorugh each tuple
    print(i) # Print each tuple
    # time.sleep(1)
    i -= 1  # Decrement the index

我想做的是以相反的顺序打印列表，从最后的元组坐标在前面，第一个元组坐标在后面。现在的问题是，当我尝试减少索引时会引发此错误：

unsupported operand type(s) for -=: 'tuple' and 'int'

有人知道为什么吗？

Answer 1

您可以通过以下方式使用.reverse()函数：

data= [(78, -32), (54, -32), (30, -32), (30, -8), (30, 16), (30, 40), (30, 64), 
       (6, 64), (-18, 64), (-42, 64), (-66, 64), (-66, 88), (-90, 88), (-114, 88)]
data.reverse()
print(data)

Answer 2

您可以使用切片来完成此操作！

x = [(78, -32), (54, -32), (30, -32), (30, -8), (30, 16), (30, 40), (30, 64), (6, 64), (-18, 64), (-42, 64), (-66, 64), (-66, 88), (-90, 88), (-114, 88)]

print(x[::-1])

输出

[(-114, 88), (-90, 88), (-66, 88), (-66, 64), (-42, 64), (-18, 64), (6, 64), (30, 64), (30, 40), (30, 16), (30, -8), (30, -32), (54, -32), (78, -32)]

Answer 3

在这里，i是用于迭代tech列表的变量，因此，如果要向后打印项目，则将每个元组减1都不起作用。

print(*reversed(tech),sep="\n")

就地反向：-）

tech.reverse()

还是在每次迭代中使用不同的变量（您的意图是减少i？）

for x in tech: # Loop thorugh each tuple
    print(x) # Print each tuple
    # time.sleep(1)
    i -= 1  # Decrement the index

Answer 4

l = [(78, -32), (54, -32), (30, -32), (30, -8), (30, 16), (30, 40), (30, 64), (6, 64), (-18, 64), (-42, 64), (-66, 64), (-66, 88), (-90, 88), (-114, 88)]
print(l[::-1])

使用[::-1]将反转列表值。

如何反转列表中元组的顺序

4 个答案: