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<struct>"))
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|
+---+----------------+--------+