在Cypher中通过索引进行迭代

Question

说我已经匹配了一系列关系:

MATCH a-[r:BELONGS_TO]->b

如何迭代每个关系并为其分配索引？在伪代码中:

for i in range(0, # of r's)
  r.order = i

Answer 1

这应该工作:

MATCH (a)-[r:BELONGS_TO]->(b)
WITH collect(r) as rels
WITH rels, range(0, size(rels)) AS is
UNWIND is AS i
WITH rels[i] as rel, i
SET rel.order = i

Answer 2

你可以稍微破解一下：

MATCH (a)-[r:BELONGS_TO]->(b)
WITH collect(r) as relationships
UNWIND range(0, size(relationships)-1) as x
RETURN relationships[x]