如何在列表中添加相邻的数字？我无法获取最后一个变量

您可以将其写成列表理解，注意sa中的第i个元素是从x[i-1]到x[i+1]的x值中的sum。现在这些索引可能会超出x的边界，所以我们需要使用max和min来将它们保持在范围内：

x = [3, 8, -2, 6, 9, -4, 7, 1, -5, 8]
sa = [sum(x[max(i-1, 0):min(i+2, len(x))]) for i in range(len(x))]
print(sa)

输出：

[11, 9, 12, 13, 11, 12, 4, 3, 4, 3]

如果您正在寻找非全面的方法，这里就是。

for i in range(len(x)):
if i == 0:
sa.append(x[i] + x[i+1])
elif 1 <= i < len(x)-1:
sa.append(x[i-1] + x[i] + x[i+1])
else:
sa.append(x[i] + x[i-1])
print("Here is sa", sa)

输出：

Here is sa [11, 9, 12, 13, 11, 12, 4, 3, 4, 3]

您的代码有一些错误：

x = [3, 8, -2, 6, 9, -4, 7, 1, -5, 8]
sa = []
# the last element of the loop will be x[len(x)-2], it is -5 in this case
# -5 is the last element this loop process, it adds up 1, -5 and 8
# this loop will not take 8 as the central number, so the results miss the last value
for i in range (0, len(x)-1):
if i<1:
sa.append(x[0] + x[1])
# in python, it is `and` not &, & is bitwise and.
elif i >= 1 & i< len(x):
sa.append(x[i-1] + x[i] + x[i+1])
if i == 0: # this is meaningless, i == 0 is covered in the first if branch
sa.append(x[i] + x[i+1])
print("Here is sa", sa)

修复您的代码：

x = [3, 8, -2, 6, 9, -4, 7, 1, -5, 8]
sa = []
# fix one: loop to the last element
for i in range (0, len(x)):
if i<1:
sa.append(x[0] + x[1])
# fix two: do not include the last element in this elif branch
elif i >= 1 and i < len(x) - 1:
sa.append(x[i-1] + x[i] + x[i+1])
# fix three: process the last element.
else:
sa.append(x[i - 1] + x[i])
print("Here is sa", sa)

输出：

Here is sa [11, 9, 12, 13, 11, 12, 4, 3, 4, 3]