如何将Neo4j返回类型转换为python类型 [英] How to convert neo4j return types to python types

问题描述

我正在使用py2neo，我想从查询返回中提取信息，以便可以在python中进行处理.例如，我有一个包含三个"Person"节点的数据库:

I am using py2neo and I would like to extract the information from query returns so that I can do stuff with it in python. For example, I have a DB containing three "Person" nodes:

for num in graph.cypher.execute("MATCH (p:Person) RETURN count(*)"): print num

for num in graph.cypher.execute("MATCH (p:Person) RETURN count(*)"): print num

输出:

>> count(*)

3

很抱歉，格式很糟糕，它看起来与mysql输出基本相同.但是，我想使用数字3进行计算，但是它的类型为py2neo.cypher.core.Record.如何将其转换为python int，以便可以使用它?从更一般的意义上讲，我应该如何处理密码查询，以便可以在Python中使用返回的数据?

Sorry for shitty formatting, it looks essentially the same as a mysql output. However, I would like to use the number 3 for computations, but it has type py2neo.cypher.core.Record. How can I convert this to a python int so that I can use it? In a more general sense, how should I go about processing cypher queries so that the data I get back can be used in Python?

推荐答案

graph.cypher.execute()返回包含多个Records的RecordList.每个Record都对应于Cypher查询结果的一行.

graph.cypher.execute() returns a RecordList containing multiple Records. Each Record corresponds to a single line of the result of your Cypher query.

您的RETURN count(*)查询仅返回一行，因此for num in ...循环将仅触及RecordList中的一个Record.

Your RETURN count(*) query returns only one line, so the for num in ... loop will only touch one Record in your RecordList.

要从记录的列中获取数据，可以使用索引或列名:

To get data from the columns of a record, you can use indices or column names:

for num in ... :
    your_count = num[0] # gets the first column

这应该是int，但是您现在可以使用float()或int()将其转换为所需的内容.

This should be an int, but you can now convert it to whatever you need with float() or int().

您的查询仅返回一行和一列.您可以将其缩短为:

Your query returns only one line with one column. You can shorten it to:

your_count = graph.cypher.execute("MATCH (p:Person) RETURN count(*)")[0][0]

第一个[0]获取结果RecordList的第一个Record，第二个[0]获取Record的第一列.

The first [0] gets the first Record of your resulting RecordList and the second [0] gets the first column of the Record.

看看: http://py2neo.org/2.0/cypher.html#records

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