Question

下面是我写的代码，它只检查第一个和最后一个模式，而不是中间。任何帮助深表感谢。

def arith_geo(list_n):
    if len(list_n) == 0:
        return 0

    for n in range(len(list_n) - 1): 
        if (list_n[n + 1] - list_n[n]) == (list_n[n-1] - list_n[n-2]):
            return 'Arithmetic'
        elif (list_n[n + 1] / list_n[n]) == (list_n[n -1 ] / list_n[n - 2]):
            return 'Geometric'
        else:
            return -1
print(arith_geo([1, 2, 3, 8, 5, 6]))

Answer 1

1）对长度为0,1,2（长度为2的序列有效AP或GP？）进行特殊处理

2）制作Arith_Counter和Geom_Counter变量。

3）为范围n

中的索引1..length-2创建循环

4）每一步。

  check if AP property valid - 
  if yes, increment Arith_Counter

  check if GP property valid 
  if yes, increment Geom_Counter.

5）最后检查

Arith_Counter = length - 2
or
Geom_Counter = length - 2
(or both)

这是一种简单的方法，无需提前退货（您可以在每一步后添加检查计数器）

Answer 2

感谢@MBo和@Jeremy Kahan，你的回答是很棒的指令，我和他们设法解决了这个问题。这就是我所做的：

 def arith_geo(list_n):
    if len(list_n) == 0:
        return 0
    diff = list_n[1] - list_n[0]
    div = list_n[1] / list_n[0]
    for num in range(1, len(list_n)):
        if list_n[num] - list_n[num - 1] == diff:
            counter = 'Arithmetic'
        elif list_n[num] / list_n[num-1] == div:
            counter = 'Geometric'
        else:
            counter = -1
            break
    return counter
print(arith_geo([2,4,8,16]))
print(arith_geo([1,2,3,4]))
print(arith_geo([1,2,8,3]))

Answer 3

使用all内置函数和顺序消除可能的状态，它可以非常简单地实现：

def arith_geo(list_n):

    if len(list_n) < 2:
        return "Not a progression - the list is too short"

    # ---------------------------------------------
    states = ['Arithmetic', 'Geometric'] # possible states of list_n

    b1, b2 = list_n[:2]
    adj_elements = list(zip(list_n[1:], list_n[2:]))

    # ---------------------------------------------
    # arithmetric part:
    # ---------------------------------------------

    if not all(y - x == b2 - b1 for x,y in adj_elements):
        states.remove('Arithmetic')

    # ---------------------------------------------
    # geometric part:
    # ---------------------------------------------
    # according to the definition of geometric progression:
    # b1 != 0
    # q != 0 <=> b2 != 0
    # ---------------------------------------------

    if b1 * b2 == 0 or not all(y / x == b2 / b1 for x,y in adj_elements):
        states.remove('Geometric')

    # ---------------------------------------------
    state_message = {0:"Neither arithmetic nor geometric", 
                     2:"Both arithmetic and geometric", 
                     1:(states+[''])[0]}

    return state_message[len(states)]

结果：

print(arith_geo([])) # Not a progression - the list is too short
print(arith_geo([0])) # Not a progression - the list is too short

print(arith_geo([1, 2])) # Both arithmetic and geometric
print(arith_geo([7, 7])) # Both arithmetic and geometric
print(arith_geo([7, 7, 7])) # Both arithmetic and geometric

print(arith_geo([0, 0])) # Arithmetic
print(arith_geo([0, 1])) # Arithmetic
print(arith_geo([1, 0])) # Arithmetic
print(arith_geo([0, 2, 4])) # Arithmetic
print(arith_geo([7, 5, 3])) # Arithmetic

print(arith_geo([1, 2, 4])) # Geometric
print(arith_geo([1, -0.5, 0.25])) # Geometric

print(arith_geo([0, 2, 3, 8])) # Neither arithmetic nor geometric
print(arith_geo([1, 2, 3, 8])) # Neither arithmetic nor geometric

请注意，根据几何级数的定义，该函数可区分对[0, 0]和[7, 7]，以及[0, 1]和[1, 2]。

使用python检查数字列表是算术的还是几何的

3 个答案: