仅提取邮政编码和 lsoa 代码 - sparkql [英] extracting only postcode and lsoa code - sparkql

问题描述

我正在尝试编写一些 sparkql 来提取邮政编码数据和行进 lsoa 代码.到目前为止，当我只想要最后一个单元时，我所拥有的提取了邮政编码和 lsoa 代码的所有 url.请问如何只获取最后一个元素?

I am trying to write some sparkql to extract postcode data and marching lsoa codes. what I have so far extracts all the url for both the postcodes and lsoa codes, when I would like just the last unit. How do i get just the last elements please?

query <- "PREFIX pc: <http://data.ordnancesurvey.co.uk/ontology/postcode/>
      PREFIX geo: <http://opendatacommunities.org/def/geography#>
      SELECT * WHERE { 
      ?postcodeUnit
      a pc:PostcodeUnit;
      geo:lsoa ?lsoa .
      }
      limit 10"

   endpoint <- "http://opendatacommunities.org/sparql"
   resultList <- SPARQL(endpoint,query)
   head(resultList)

我也担心当我开始工作时，R studio 会超时，我需要从 Web 服务器运行它吗?请

I am also concerned when i get this working, R studio will time out, do i need to run this from a web server? please

提前致谢

推荐答案

如果 URI 的生成方式是标准的，你可以把结果转成字符串，然后只取需要的部分:

If the way URIs are generated is standard, you can just turn the results into strings and then take only the part that is needed:

PREFIX pc: <http://data.ordnancesurvey.co.uk/ontology/postcode/>
PREFIX geo: <http://opendatacommunities.org/def/geography#>
SELECT ?postcode ?lsoa
WHERE { 
  ?URI_postcodeUnit
  a pc:PostcodeUnit;
  geo:lsoa ?URI_lsoa .
BIND (STRAFTER((STR(?URI_postcodeUnit)),"postcodeunit/") as ?postcode)
BIND (STRAFTER((STR(?URI_lsoa)),"lsoa/") as ?lsoa)
  }
  limit 10

这篇关于仅提取邮政编码和 lsoa 代码 - sparkql的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！