我正在研究图表并编写了一个用于创建图表的混合模块。我想在其中包含一些替代构造函数。 这是我的:
class Graph(GraphDegree, GraphDegreePlot, GraphGeneration, object):
def __init__(self):
self.nodes = set([])
self.edges = {}
def get_nodes(self):
"""
get nodes in graph
"""
return self.nodes
def get_number_of_nodes(self):
"""
get number of nodes in the graph
"""
return len(self.nodes)
def get_edges(self):
"""
get edges in graph
"""
return self.edges
def get_heads_in_edges(self):
"""
get heads in edges present on the graph
"""
return self.edges.values()
def add_node(self, node):
"""
add new node to graph
"""
if node in self.get_nodes():
raise ValueError('Duplicate Node')
else:
self.nodes.add(node)
self.edges[node] = []
def add_connection(self, edge):
"""
adds edge to graph
"""
origin = edge.get_origin()
destination = edge.get_destination()
if origin not in self.get_nodes() or destination not in self.get_nodes():
raise ValueError('Nodes need to be in the graph')
self.get_edges()[origin].append(destination)
self.get_edges()[destination].append(origin)
def get_children(self, node):
"""
Returns the list of nodes node node is connected to
"""
return self.get_edges()[node]
class GraphGeneration(object):
@classmethod
def gen_graph_from_text(cls, file):
'''
Generate a graph from a txt. Each line of the txt begins with the source node and then the destination nodes follow
'''
cls.__init__()
file = open(file, 'r')
for line in file:
origin = line[0]
destinations = line[1:-1]
cls.add_node(origin)
for destination in destinations:
cls.add_node(destination)
edge = Edge(origin, destination)
cls.add_connection(edge)
graph = Graph.gen_graph_from_text(file)
我希望它返回一个图形,其中节点和边是从文件生成的。我写的方法不管用,不知道有没有意义。我想要做的是在该方法中使用 Graph 的 __init__
方法,然后从文件中添加边和节点。我可以只编写一个实例级方法来执行此操作,但我想到了其他替代初始化程序。
谢谢!
最佳答案
在您的替代构造函数中,使用 cls
创建该类的新实例。然后,像往常一样使用 self
并在最后返回它。
注意:cls
是对类本身的引用,而不是您期望的实例。将所有出现的 cls
替换为 self
除了实例化应该会给你你想要的结果。例如,
@classmethod
def gen_graph_from_text(cls, file):
self = cls()
file = open(file, 'r')
for line in file:
origin = line[0]
destinations = line[1:-1]
self.add_node(origin)
for destination in destinations:
self.add_node(destination)
edge = Edge(origin, destination)
self.add_connection(edge)
return self
关于python - Python 中的替代构造函数,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31011143/