不放回抽样用awk [英] Sampling without replacement using awk

问题描述

我有很多的文本文件看起来像这样的：

I have a lot of text files that look like this:

>ALGKAHOLAGGATACCATAGATGGCACGCCCT
>BLGKAHOLAGGATACCATAGATGGCACGCCCT
>HLGKAHOLAGGATACCATAGATGGCACGCCCT
>DLGKAHOLAGGATACCATAGATGGCACGCCCT
>ELGKAHOLAGGATACCATAGATGGCACGCCCT
>FLGKAHOLAGGATACCATAGATGGCACGCCCT
>JGGKAHOLAGGATACCATAGATGGCACGCCCT
>POGKAHOLAGGATACCATAGATGGCACGCCCT

有没有办法用awk做了采样，无需更换？

Is there a way to do a sampling without replacement using awk?

例如，我有这样的8行，我只是想品尝这些随机在一个新的文件4，无需更换。
输出应该是这个样子：

For example, I have this 8 lines, and I only want to sample 4 of these randomly in a new file, without replacement. The output should look something like this:

>FLGKAHOLAGGATACCATAGATGGCACGCCCT
>POGKAHOLAGGATACCATAGATGGCACGCCCT    
>ALGKAHOLAGGATACCATAGATGGCACGCCCT
>BLGKAHOLAGGATACCATAGATGGCACGCCCT

在此先感谢

推荐答案

这个怎么样对你行10％的随机抽样？

How about this for a random sampling of 10% of your lines?

awk 'rand()>0.9' yourfile1 yourfile2 anotherfile

我不知道你所说的替代品的意思...有发生在这里没有更换，只是随机选择。

I am not sure what you mean by "replacement"... there is no replacement occurring here, just random selection.

基本上，它看起来在每个文件$ P $的每一行pcisely一次并在区间0到1产生一个随机数如果随机数大于0.9，线路输出。因此，基本上是滚动10面的骰子的每一行，如果骰子出来作为10正在打印线没有机会只有两次打印出来 - 除非它在文件中出现了两次，当然

Basically, it looks at each line of each file precisely once and generates a random number on the interval 0 to 1. If the random number is greater than 0.9, the line is output. So basically it is rolling a 10 sided dice for each line and only printing it if the dice comes up as 10. No chance of a line being printed twice - unless it occurs twice in your files, of course.

有关由@klashxx建议增加随机性（！），你可以添加一个函数srand（）在开始

For added randomness (!) you can add an srand() at the start as suggested by @klashxx

awk 'BEGIN{srand()} rand()>0.9' yourfile(s)

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