用于匹配所有可能的成对字符串的嵌套循环的Python

我正在尝试完成一个值集之间所有可能路由的列表。我的当前数据集是一组列表，每个列表包含一对值（输入和输出）

List = [[0.5,1],[0.75,1],[0.5,1.5],[0.75,1.5],[1,1.5],[0.5,2],[0.75,2],[1,2],[1.5,2],[0.75,3],[1,3],[1.5,3],[2,3],[1,4],[1.5,4],[2,4],[3,4],[1.5,6],[2,6],[3,6],[4,6],[3,8],[2,8],[4,8],[6,8],[3,10],[4,10],[6,10],[8,10],[4,12],[6,12],[8,12],[10,12],[6,14],[8,14],[10,14],[12,14],[6,16],[8,16],[10,16],[12,16],[14,16],[10,18],[12,18],[14,18],[16,18],[10,20],[12,20],[14,20],[16,20],[18,20],[14,24],[16,24],[18,24],[20,24],[22,24],[18,26],[20,26],[22,26],[24,26],[18,28],[20,28],[24,28],[26,28],[20,30],[24,30],[26,30],[28,30],[24,32],[26,32],[28,32],[30,32],[24,34],[26,34],[30,34],[32,34],[24,36],[26,36],[30,36],[32,36],[34,36],[24,42],[26,42],[30,42],[32,42],[34,42],[36,42],[36,48],[40,48],[42,48],[44,48],[46,48]]

我需要找到一种方法，将这些结合起来，列出所有值之间的所有路线，例如，对于0.5-2之间的所有路线，它将列出类似的内容：

[0.5,2];[0.5,1][1,2];[0.5,1][1,1.5][1.5,2];[0.5,1.5][1.5,2]

---

我相信在Python中使用for循环是可能的，但我是一个新手，我唯一的解决方案是通过嵌套尽可能多的循环对，这是非常麻烦的，并且在执行时很容易出错，我不确定是否有其他或更简化的方法。任何帮助都将不胜感激

您知道这将产生大量路由，如果您的列表变得更大，计算可能需要很长时间

您可以做的是逐步建立一个路由列表，通过将对连接到您迄今为止拥有的路由的开始或结束而形成的新路由来扩展该列表：

List = [[0.5,1],[0.75,1],[0.5,1.5],[0.75,1.5],[1,1.5],[0.5,2],[0.75,2],[1,2],[1.5,2],[0.75,3],[1,3],[1.5,3],[2,3],[1,4],[1.5,4],[2,4],[3,4],[1.5,6],[2,6],[3,6],[4,6],[3,8],[2,8],[4,8],[6,8],[3,10],[4,10],[6,10],[8,10],[4,12],[6,12],[8,12],[10,12],[6,14],[8,14],[10,14],[12,14],[6,16],[8,16],[10,16],[12,16],[14,16],[10,18],[12,18],[14,18],[16,18],[10,20],[12,20],[14,20],[16,20],[18,20],[14,24],[16,24],[18,24],[20,24],[22,24],[18,26],[20,26],[22,26],[24,26],[18,28],[20,28],[24,28],[26,28],[20,30],[24,30],[26,30],[28,30],[24,32],[26,32],[28,32],[30,32],[24,34],[26,34],[30,34],[32,34],[24,36],[26,36],[30,36],[32,36],[34,36],[24,42],[26,42],[30,42],[32,42],[34,42],[36,42],[36,48],[40,48],[42,48],[44,48],[46,48]]

routes = []
for pair in List:
    inValue,outValue = pair
    newRoutes = [[pair]]
    for path in routes:
        if path[0][0] == outValue:
            newRoutes.append([pair] + path)
        if path[-1][-1] == inValue:
            newRoutes.append(path + [pair])
    routes.extend(newRoutes)

输出：

print("number of routes:",len(routes))
for route in routes[:10]:
    print(route)
print("...")
for route in routes[-10:]:
    print(route)

number of routes: 5646987
[[0.5, 1]]
[[0.75, 1]]
[[0.5, 1.5]]
[[0.75, 1.5]]
[[1, 1.5]]
[[0.5, 1], [1, 1.5]]
[[0.75, 1], [1, 1.5]]
[[0.5, 2]]
[[0.75, 2]]
[[1, 2]]
...
[[0.75, 1], [1, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[22, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[44, 48]]
[[46, 48]]

for route in findRoutes(List):
    if len(route) == 5:
       print("first 5 step route:",route)
       break

# first 5 step route: [[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4]]

List = [[0.5,1],[0.75,1],[0.5,1.5],[0.75,1.5],[1,1.5],[0.5,2],[0.75,2],[1,2],[1.5,2],[0.75,3],[1,3],[1.5,3],[2,3],[1,4],[1.5,4],[2,4],[3,4],[1.5,6],[2,6],[3,6],[4,6],[3,8],[2,8],[4,8],[6,8],[3,10],[4,10],[6,10],[8,10],[4,12],[6,12],[8,12],[10,12],[6,14],[8,14],[10,14],[12,14],[6,16],[8,16],[10,16],[12,16],[14,16],[10,18],[12,18],[14,18],[16,18],[10,20],[12,20],[14,20],[16,20],[18,20],[14,24],[16,24],[18,24],[20,24],[22,24],[18,26],[20,26],[22,26],[24,26],[18,28],[20,28],[24,28],[26,28],[20,30],[24,30],[26,30],[28,30],[24,32],[26,32],[28,32],[30,32],[24,34],[26,34],[30,34],[32,34],[24,36],[26,36],[30,36],[32,36],[34,36],[24,42],[26,42],[30,42],[32,42],[34,42],[36,42],[36,48],[40,48],[42,48],[44,48],[46,48]]

for path in findPath(List,1,3):
    print(path)


[[1, 1.5], [1.5, 2], [2, 3]]
[[1, 1.5], [1.5, 3]]
[[1, 2], [2, 3]]
[[1, 3]]

请注意，这可以通过索引现有路由的第一个/最后一个值来优化。这样的优化将使速度提高一倍，但不会减少输出中的路由数：

routesFirst = dict()
routesLast  = dict()
routes      = []
for pair in List:
    inValue,outValue = pair
    newRoutes = [[pair]]
    for path in routesFirst.get(outValue,[]):
        newRoutes.append([pair]+path)
    for path in routesLast.get(inValue,[]):
        newRoutes.append(path+[pair])
    routes.extend(newRoutes)
    routesFirst.setdefault(inValue,[]).extend(newRoutes)
    routesLast.setdefault(outValue,[]).extend(newRoutes)

[编辑]递归方法（添加用于良好测量）：

如果不打算遍历所有路径，可以创建一个递归生成器函数，该函数将逐个返回这些路径。您可以在一个for循环（例如）中使用它，当满足某个条件时，您打算中断该循环

下面是一个非常简单的示例（未使用meoization或任何优化）：

输出：

print("number of routes:",len(routes))
for route in routes[:10]:
    print(route)
print("...")
for route in routes[-10:]:
    print(route)

number of routes: 5646987
[[0.5, 1]]
[[0.75, 1]]
[[0.5, 1.5]]
[[0.75, 1.5]]
[[1, 1.5]]
[[0.5, 1], [1, 1.5]]
[[0.75, 1], [1, 1.5]]
[[0.5, 2]]
[[0.75, 2]]
[[1, 2]]
...
[[0.75, 1], [1, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[22, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[44, 48]]
[[46, 48]]

for route in findRoutes(List):
    if len(route) == 5:
       print("first 5 step route:",route)
       break

# first 5 step route: [[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4]]

List = [[0.5,1],[0.75,1],[0.5,1.5],[0.75,1.5],[1,1.5],[0.5,2],[0.75,2],[1,2],[1.5,2],[0.75,3],[1,3],[1.5,3],[2,3],[1,4],[1.5,4],[2,4],[3,4],[1.5,6],[2,6],[3,6],[4,6],[3,8],[2,8],[4,8],[6,8],[3,10],[4,10],[6,10],[8,10],[4,12],[6,12],[8,12],[10,12],[6,14],[8,14],[10,14],[12,14],[6,16],[8,16],[10,16],[12,16],[14,16],[10,18],[12,18],[14,18],[16,18],[10,20],[12,20],[14,20],[16,20],[18,20],[14,24],[16,24],[18,24],[20,24],[22,24],[18,26],[20,26],[22,26],[24,26],[18,28],[20,28],[24,28],[26,28],[20,30],[24,30],[26,30],[28,30],[24,32],[26,32],[28,32],[30,32],[24,34],[26,34],[30,34],[32,34],[24,36],[26,36],[30,36],[32,36],[34,36],[24,42],[26,42],[30,42],[32,42],[34,42],[36,42],[36,48],[40,48],[42,48],[44,48],[46,48]]

for path in findPath(List,1,3):
    print(path)


[[1, 1.5], [1.5, 2], [2, 3]]
[[1, 1.5], [1.5, 3]]
[[1, 2], [2, 3]]
[[1, 3]]

[EDIT2]查找从一个号码到另一个号码的路径

为了帮助理解生成器，我实现了一个简单的变体，它只返回连接两个特定数字的路径。它仍然需要使用递归，但不是遍历所有可能的连接，而是只查看从给定原点开始并在到达目标时停止的连接。对于多步路径，对从原点连接的每个可能的outValue调用相同的函数

def findPath(pairs,origin,destination):
    for pair in pairs:
        inValue,outValue = pair
        if inValue != origin:
            continue
        if outValue == destination :
            yield [pair]
            continue
        for subPath in findPath(pairs,outValue,destination):
            yield [pair] + subPath

输出：

print("number of routes:",len(routes))
for route in routes[:10]:
    print(route)
print("...")
for route in routes[-10:]:
    print(route)

number of routes: 5646987
[[0.5, 1]]
[[0.75, 1]]
[[0.5, 1.5]]
[[0.75, 1.5]]
[[1, 1.5]]
[[0.5, 1], [1, 1.5]]
[[0.75, 1], [1, 1.5]]
[[0.5, 2]]
[[0.75, 2]]
[[1, 2]]
...
[[0.75, 1], [1, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[0.75, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4], [4, 6], [6, 8], [8, 10], [10, 12], [12, 14], [14, 16], [16, 18], [18, 20], [20, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[22, 24], [24, 26], [26, 28], [28, 30], [30, 32], [32, 34], [34, 36], [36, 42], [42, 48]]
[[44, 48]]
[[46, 48]]

for route in findRoutes(List):
    if len(route) == 5:
       print("first 5 step route:",route)
       break

# first 5 step route: [[0.5, 1], [1, 1.5], [1.5, 2], [2, 3], [3, 4]]

List = [[0.5,1],[0.75,1],[0.5,1.5],[0.75,1.5],[1,1.5],[0.5,2],[0.75,2],[1,2],[1.5,2],[0.75,3],[1,3],[1.5,3],[2,3],[1,4],[1.5,4],[2,4],[3,4],[1.5,6],[2,6],[3,6],[4,6],[3,8],[2,8],[4,8],[6,8],[3,10],[4,10],[6,10],[8,10],[4,12],[6,12],[8,12],[10,12],[6,14],[8,14],[10,14],[12,14],[6,16],[8,16],[10,16],[12,16],[14,16],[10,18],[12,18],[14,18],[16,18],[10,20],[12,20],[14,20],[16,20],[18,20],[14,24],[16,24],[18,24],[20,24],[22,24],[18,26],[20,26],[22,26],[24,26],[18,28],[20,28],[24,28],[26,28],[20,30],[24,30],[26,30],[28,30],[24,32],[26,32],[28,32],[30,32],[24,34],[26,34],[30,34],[32,34],[24,36],[26,36],[30,36],[32,36],[34,36],[24,42],[26,42],[30,42],[32,42],[34,42],[36,42],[36,48],[40,48],[42,48],[44,48],[46,48]]

for path in findPath(List,1,3):
    print(path)


[[1, 1.5], [1.5, 2], [2, 3]]
[[1, 1.5], [1.5, 3]]
[[1, 2], [2, 3]]
[[1, 3]]

---

这是一张图表。考虑使用图形库来帮助HMM，他们在这个问题上实际上没有答案。也许我会去回答它。谢谢你，我现在已经开始考虑把问题作为一个网络来表达，而且看起来它对NETWorkX来说是可行的。一旦我开始思考它，你可能需要考虑一个生成器。这就需要递归性，因为OP指出他/她是一个好点，+1，所以我选择不使用。但我想让大家注意到，这应该是一个发电机，即使他们还没有了解它。：）谢谢你的回答，作为一个新手，我觉得有些问题比我略高，但我将尝试从你的扩展答案中了解更多。为了这个练习的目的，我只想找到所有路线，但现在我已经看到了总数（5646987！！）我意识到，我可能应该使用一种只生成我需要的内容的方法，而不是试图将它们存储为列表并搜索我需要的内容。我将研究使用生成器方法来查找一组点之间的所有点