[英]How i can define schema for array using jsonloader?
我正在使用Elephantbird项目将json文件加载到Pig。 但是我不确定如何在加载时定义架构。 找不到相同的描述。
数据:
{"id":22522,"name":"Product1","colors":["Red","Blue"],"sizes":["S","M"]}
{"id":22523,"name":"Product2","colors":["White","Blue"],"sizes":["M"]}
码:
feed = LOAD '$INPUT' USING com.twitter.elephantbird.pig.load.JsonLoader() AS products_json;
extracted_products = FOREACH feed GENERATE
products_json#'id' AS id,
products_json#'name' AS name,
products_json#'colors' AS colors,
products_json#'sizes' AS sizes;
describe extracted_products;
结果:
extracted_products: {id: chararray,name: bytearray,colors: bytearray,sizes: bytearray}
我如何才能给它们正确的架构(整数,字符串,数组,数组),以及如何将数组元素展平为行?
提前致谢
将json数组转换为元组:
feed = LOAD '$INPUT' USING com.twitter.elephantbird.pig.load.JsonLoader() AS products_json;
extracted_products = FOREACH feed GENERATE
products_json#'id' AS id:chararray,
products_json#'name' AS name:chararray,
products_json#'colors' AS colors:{t:(i:chararray)},
products_json#'sizes' AS sizes:{t:(i:chararray)};
扁平化一个元组
flattened = foreach extracted_products generate id,flatten(colors);
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.