問題內容
我是 spark 新手。我試圖展平數據框，但未能通過“爆炸”做到這一點。
原始數據框架構如下：
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"}]
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我需要將其轉換為以下架構？
id|approvaltype|status 1|1st line manager|approved 1|2nd line manager|approved 2|1st line manager|approved 2|2nd line manager|rejected
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我已經嘗試過
df_exploded = df.withcolumn("approvaljson", explode("approvaljson"))
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但是我得到了錯誤：
Cannot resolve "explode(ApprovalJSON)" due to data type mismatch:
parameter 1 requires ("ARRAY" or "MAP") type, however, "ApprovalJSON"
is of "STRING" type.;
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正確答案
首先將類似 json 的字符串解析為結構數組，然后使用 inline 將數組分解為行和列
df1 = df.withcolumn("approvaljson", f.from_json("approvaljson", schema="array"))
df1 = df1.select("id", f.inline('approvaljson'))
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結果
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| +---+----------------+--------+
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