Python，如何计算列表之间的差异

Question

我有清单

a = [('A', 10, 7), ('B', 30, 5), ('C', 73, 12), ('D', 3, 12)]

并且需要计算此列表中两个相邻点之间的差。

例如，（B-A），（C-B），（D-C）并获得此输出：

output = [(20, -2), (43, 7), (-70, 0)

有没有快速的方法？

Answer 1

如果将邻居变成成对，这个问题就变得微不足道了。这是把戏。

a = [('A', 10, 7), ('B', 30, 5), ('C', 73, 12), ('D', 3, 12)]

firsts = a[:-1]  # a without the last element.
seconds = a[1:]  # a without the first element.
pairs = zip(firsts, seconds)

print(list(pairs))  # To understand how it works.

for (first, second) in pairs:
  # Here first would be e.g. ('A', 10, 7),
  # and second would be e.g. ('B', 30, 5)
  # You can handle the rest yourself.
  pass

Answer 2

您可以使用列表理解：

a = [('A', 10, 7), ('B', 30, 5), ('C', 73, 12), ('D', 3, 12)]

result = [ (second - a[i+1][1], third - a[i+1][2] )   for i, (first, second, third) in enumerate(a[:-1]) ]
print(result)

Answer 3

for i,x in enumerate(a[:-1]):
    output.append((a[i+1][1]-a[i][1],a[i+1][2]-a[i][2]))

Answer 4

使用列表理解]的可能解决方案可能是：

a = [('A', 10, 7), ('B', 30, 5), ('C', 73, 12), ('D', 3, 12)]
diff = [ (a[i+1][1] - a[i][1], a[i+1][2] - a[i][2]) for i in range(len(a)-1)]
print(diff)