apoc.path.slice

详细信息

语法

apoc.path.slice(path [, offset, length ])

描述

从给定的 PATH 中,按照指定的偏移量和长度截取并返回一个新的 PATH

参数

名称

类型

描述

path

PATH

要进行截取的路径。

offset

INTEGER(整数)

新路径开始的偏移量。默认值为:0

length

INTEGER(整数)

新路径的长度。默认值为:-1

返回

PATH

使用示例

本节中的示例基于以下示例图

MERGE (manUtd:Club {name: 'Man Utd'})
MERGE (juventus:Club {name: 'Juventus'})
MERGE (flamengo:Club {name: 'Flamengo'})

MERGE (premierLeague:League {name: 'Premier League'})
MERGE (serieA:League {name: 'Serie A'})
MERGE (brasileirao:League {name: 'Brasileirão'})

MERGE (england:Country {name: 'England'})
MERGE (brazil:Country {name: 'Brazil'})

MERGE (uefa:Confederation {name: 'UEFA'})

MERGE (manUtd)-[:IN_LEAGUE]->(premierLeague)
MERGE (premierLeague)-[:IN_COUNTRY]->(england)
MERGE (england)-[:IN_CONFEDERATION]->(uefa)

MERGE (juventus)-[:IN_LEAGUE]->(serieA)

MERGE (flamengo)-[:IN_LEAGUE]->(brasileirao)
MERGE (brasileirao)-[:IN_COUNTRY]->(brazil);

apoc.path.slice 函数返回路径的一个子集,该子集从指定的偏移量开始,包含指定数量的元素。

以下示例返回组合路径的一个子集,从偏移量 1 开始,长度为 1:

MATCH (club:Club)
OPTIONAL MATCH path1 = (club)-[:IN_LEAGUE]->(league)
OPTIONAL MATCH path2 = (league)-[:IN_COUNTRY]->(country)
WITH apoc.path.combine(path1, path2) AS path
RETURN apoc.path.slice(path, 1, 1);
结果
apoc.path.slice(path, 1, 1)

(:League {name: "Premier League"})-[:IN_COUNTRY]→(:Country {name: "England"})

(:League {name: "Serie A"})

(:League {name: "Brasileirão"})-[:IN_COUNTRY]→(:Country {name: "Brazil"})