转换“元组列表"进入平面列表或矩阵 [英] Transform "list of tuples" into a flat list or a matrix

问题描述

使用Sqlite，"select..from"命令返回结果输出"，该结果打印(在python中):

With Sqlite, a "select..from" command returns the results "output", which prints (in python):

>>print output
[(12.2817, 12.2817), (0, 0), (8.52, 8.52)]

这似乎是一个元组列表.我想将输出"转换为简单的1D数组(我猜是Python中的列表):

It seems to be a list of tuples. I would like to either convert "output" in a simple 1D array (=list in Python I guess):

[12.2817, 12.2817, 0, 0, 8.52, 8.52]

或2x3矩阵:

12.2817 12.2817
0          0 
8.52     8.52

通过"output [i] [j]"读取

to be read via "output[i][j]"

flatten命令不执行第一个选项的工作，而我不知道第二个选项...:)

The flatten command does not do the job for the 1st option, and I have no idea for the second one... :)

能给我一个提示吗?快速的事情会变得很棒，因为实际数据会更大(这只是一个简单的示例).

Could you please give me a hint? Some thing fast would be great as real data are much bigger (here is just a simple example).

推荐答案

到目前为止，发布的最快(也是最短)解决方案是:

By far the fastest (and shortest) solution posted:

list(sum(output, ()))

比itertools解决方案快约50％，比map解决方案快约70％.

About 50% faster than the itertools solution, and about 70% faster than the map solution.

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