在Cypher查询中使用正则表达式捕获组 [英] Using regex capture groups in a Cypher query

问题描述

在密码文档中，它说您可以使用正则表达式匹配字符串属性中特定的(以前已知的)模式.

是否也可以使用捕获组?

举个例子:

我的节点属性是序列化的JSON，如下所示:

n.json = '{"name": "John", "gender": "m"}'
n.json = '{"name": "Jane", "gender": "f"}'

我想知道不同性别的人之间的关系:

MATCH r=(n)--(m)
WHERE NOT (n.json =~ '.*gender": "(\c)".*')[1] = (m.json =~ '.*gender": "(\c)".*')[1]
RETURN r

或类似的东西.

解决方案

此处是一个相关的问题.简短的答案是cypher不支持反向引用.正则表达式仅用于匹配.

通常，当我遇到您所面临的问题时，我会尝试在导入步骤之前进行处理. IE.您可以从数据开始，将其处理为CSV，然后将CSV加载到图形中.在处理CSV的过程中，我将与其他一些工具(sed/awk/perl/python/其他)进行模式匹配，然后在将数据加载到图形中之前先对其进行修改.

In the cypher documentation it says you can use regexes to match particular -previously known- patterns in a string attribute.

Is it possible to use capture groups as well?

Take an example:

My node attributes are serialised JSON that look like:

n.json = '{"name": "John", "gender": "m"}'
n.json = '{"name": "Jane", "gender": "f"}'

I want to know relationships between people of different gender:

MATCH r=(n)--(m)
WHERE NOT (n.json =~ '.*gender": "(\c)".*')[1] = (m.json =~ '.*gender": "(\c)".*')[1]
RETURN r

or something like that.

解决方案

Here is a related question. The short answer is that backreferences aren't supported in cypher; regular expressions are just for matching.

In general, when I run into problems like what you're facing, I try to deal with them prior to the import step. I.e. you might start with data, massage it into CSV, and then load the CSV into a graph. During the manipulation of the CSV, I'd do the pattern matching with some other tool (sed/awk/perl/python/whatever) and then modify the data before it gets loaded into the graph to do this sort of thing.

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