问题内容
我是 spark 新手。我试图展平数据框，但未能通过“爆炸”做到这一点。
原始数据框架构如下：
id|approvaljson
1|[{"approvertype":"1st line manager","status":"approved"},{"approvertype":"2nd line manager","status":"approved"}]
2|[{"approvertype":"1st line manager","status":"approved"},{"approvertype":"2nd line manager","status":"rejected"}]
我需要将其转换为以下架构？
id|approvaltype|status 1|1st line manager|approved 1|2nd line manager|approved 2|1st line manager|approved 2|2nd line manager|rejected
我已经尝试过
df_exploded = df.withcolumn("approvaljson", explode("approvaljson"))
但是我得到了错误：
Cannot resolve "explode(ApprovalJSON)" due to data type mismatch:
parameter 1 requires ("ARRAY" or "MAP") type, however, "ApprovalJSON"
is of "STRING" type.;
正确答案
首先将类似 json 的字符串解析为结构数组，然后使用 inline 将数组分解为行和列
df1 = df.withcolumn("approvaljson", f.from_json("approvaljson", schema="array>"))
df1 = df1.select("id", f.inline('approvaljson'))
结果
df1.show() +---+----------------+--------+ | ID| ApproverType| Status| +---+----------------+--------+ | 1|1st Line Manager|Approved| | 1|2nd Line Manager|Approved| | 2|1st Line Manager|Approved| | 2|2nd Line Manager|Rejected| +---+----------------+--------+
