Question

我从txt文件中读取了一个矩阵，但我无法在其上调用特定元素

矩阵：

['5x5\n', 
 '0.49832186379667975\t0.08107739538827341\t0.34862619622310764\t0.6371236836985522\t0.38901192241601756\t\n'...

代码：

f = open('matrix.txt','r+')
lines=f.readlines()
print(lines[1][2])
>>>4

但它应该是0.34862619622310764 我该如何编入索引？

Answer 1

您正在索引字符串，而不是列表。您看到的是readValue(objectNode)，而不是'4'。（为清楚起见，请勿使用4或使用print(x)。）

你忘记了每行print(repr(x))。

这样做的典型方法是：

.split('\t')

如果您想将字符串转换为实际数字，请不要忘记在整个过程中解析它们：

with open('matrix.txt') as f:
  lines = [line.split('\t') for line in f]
# Here the file auto-closes

number_lines = [[float(s) for s in line.split('\t') if s] for line in f]部分是必需的，因为您的行包含尾随if s，因此吐出后的列表将包含无法转换为数字的'\t'。空字符串是假的，因此它将被过滤掉。

但是第一行会失败;所以你必须以不同的方式处理它：

''

Answer 2

就这样：

def ucs(G, v):
    visited = set()                  # set of visited nodes
    q = queue.PriorityQueue()        # we store vertices in the (priority) queue as tuples 
                                     # (f, n, path), with
                                     # f: the cumulative cost,
                                     # n: the current node,
                                     # path: the path that led to the expansion of the current node
    q.put((0, v, [v]))               # add the starting node, this has zero *cumulative* cost 
                                     # and it's path contains only itself.

    while not q.empty():             # while the queue is nonempty
        f, current_node, path = q.get()
        visited.add(current_node)    # mark node visited on expansion,
                                     # only now we know we are on the cheapest path to
                                     # the current node.

        if current_node.is_goal:     # if the current node is a goal
            return path              # return its path
        else:
            for edge in in current_node.out_edges:
                child = edge.to()
                if child not in visited:
                    q.put((current_node_priority + edge.weight, child, path + [child]))

来自txt文件的索引矩阵

2 个答案: