Create Neo4j Nodes by passing a data variable in Python

Question

I work with a large data set in Python and would like to create Neo4j nodes out of a data array within Python. So, my naive attempt to do so would be something like the following.

(In Python script)

Product_IDs = data_array[1:1000] # This contains a list of product IDs

tot_node_num = len(Product_IDs) # It states the total number of product IDs

graph = Graph()

tx = graph.cypher.begin()

tx.append("FOREACH (r IN range(1,tot_node_num) | CREATE (:Product {ID:Product_IDs[r]}))")

tx.commit()

With the above statement, the variables: tot_node_num and Product_IDs are not recognized. How can I pass down an array that I created with my python script to create nodes in Neo4j graph database?

Thank you!

Answer 1

You're absolutely right - the best way to pass in variables is via parameters. Bear in mind however that while this works for expressions and property values, parameters cannot be used for labels and relationship types. To help with this, py2neo provides the cypher_escape function (http://py2neo.org/2.0/cypher.html#py2neo.cypher.cypher_escape):

>>> from py2neo.cypher import cypher_escape
>>> rel_type = "KNOWS WELL"
>>> "MATCH (a)-[:%s]->(b) RETURN a, b" % cypher_escape(rel_type)
'MATCH (a)-[:`KNOWS WELL`]->(b) RETURN a, b'