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[ memo ] connect a list of lists and seperate them

admin 11月 14, 2020 0

Result:


Before	After

首先说明：由于数据量原因，下方的操作都避免使用完整循环结构，尽量使用pandas的操作以及列表生成式
首先计算每个transfers中有多少个vout

1	transfers['outcount'] = transfers.vout.apply(len)

根据这个outcount创建一个嵌套列表

1 2	counts = list(transfers.outcount) ids = [[i]*counts[i] for i in range(len(transfers))]

然后拼接这个嵌套列表

1	idss = [x for j in ids for x in j]

接下来拼接vouts

1 2	vouts = [x for j in list(transfers.vout) for x in j] vouts = pd.DataFrame(vouts)

最后，将两个拼接后的列表组合：

1	vouts['txid'] = idss