英文:
how to print all result from Gremlin traversal
问题
Sure, here's the translated content:
我有一个拓扑，它是
aws_vpc<------(组成)------test---(隶属)---->location
因此我使用以下查询
graph.traversal().V().hasLabel("test").or(
__.out("隶属").hasLabel("location"),
__.out("组成").hasLabel("aws_vpc"))
来选择它，但如何打印出所有元素的名称，
我希望输出：test，隶属，location，组成，aws_vpc。
有办法实现这个吗？
英文:
I have a topology, it is
aws_vpc<------(composition)------test---(membership)---->location
So I use query
graph.traversal().V().hasLabel("test").or(
__.out("membership").hasLabel("location"),
__.out("composition").hasLabel("aws_vpc"))
to select it, but how to print all elements' name,
I want to output : test, membership, location,composition, aws_vpc.
Is there a way to achieve this?
答案1
得分: 1
你编写了一个遍历，仅检测“test”顶点是否具有传出的与“location”顶点相邻的“membership”边缘，或具有传出的与“aws_vpc”顶点相邻的“composition”边缘，因此该遍历将仅返回与该筛选条件匹配的“test”顶点。它不会比此更多地“选择”任何内容。实际上，or() 一旦在按照它们提供给 or() 的顺序返回单个 __.out("membership").hasLabel("location") 或 __.out("composition").hasLabel("aws_vpc")，就会立即满足条件，因此您甚至不会遍历所有这些路径（对于过滤操作来说，这是一件好事）。
如果您想要返回您描述的所有数据，您需要以一种方式编写查询，以便遍历所有数据并将其转换为要返回的格式。在您的情况下，一个简单的方法是使用 project()：
g.V().hasLabel('test').
project('data','memberships', 'compositions').
by(__.elementMap()).
by(__.outE("membership").as('e').
inV().hasLabel("location").as('v').
select('e','v').
by(elementMap()).
fold()).
by(__.outE("composition").as('e').
inV().hasLabel("aws_vpc").as('v').
select('e','v').
by(elementMap()).
fold())
这将对每个“test”顶点进行转换，并将其转换为具有三个键的 Map："data"，"memberships" 和 "competitions"，然后每个 by() 调节器指定了对正在转换的当前“test”顶点的处理方式，并将其放入相应的键中。请注意，我选择了 select() 来获取边缘和顶点的组合，但如果您愿意，这也可以是 project() 步骤。关键是要以 fold() 结束，以便将每个“test”顶点的边缘数据流减少为可以放入相关的“memberships”和“compositions”键中的数据列表。
英文:
You've written a traversal that only detects if "test" vertices have outgoing "membership" edges that have adjacent "location" vertices OR outgoing "composition" edges that have adjacent "aws_vpc" vertices, so all that traversal will return is "test" vertices that match that filter. It does not "select" anything more than that. In fact, the or() is immediately satisfied as soon as a single __.out("membership").hasLabel("location") or __.out("composition").hasLabel("aws_vpc") is returned in the order they are provided to or() so you don't even traverse all of those paths (which is a good thing for a filtering operation).
If you want to return all of the data you describe, you need to write your query in such a way so as to traverse it all and transform it into a format to return. A simple way to do this in your case would be to use project():
g.V().hasLabel('test').
project('data','memberships', 'compositions').
by(__.elementMap()).
by(__.outE("membership").as('e').
inV().hasLabel("location").as('v').
select('e','v').
by(elementMap()).
fold()).
by(__.outE("composition").as('e').
inV().hasLabel("aws_vpc").as('v').
select('e','v').
by(elementMap()).
fold())
This takes each "test" vertex and transforms it to a Map with three keys: "data", "memberships" and "competitions" and then each by() modulator specifies what to do with the current "test" vertex being transformed and places it in the respective key. Note that I chose select() to get the edge and vertex combinations but that could have been a project() step as well if you liked. The key there is to end with fold() so that you reduce the stream of edge data for each "test" vertex to a List of data that can put in the related "memberships" and "compositions" keys.
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