取文本部分列，再处理
【问题】
I can use awk to print the nth column from a file; the cut command also can do a similar thing.. but I require the column to be taken based on its name, for example:
col1 col2 col3 col4
2 5 3 1
6 4 7 1
3 6 5 9
7 9 7 8
and if I give a list of column names as input: e.g. col1, col3 (is is going to be a long list of column names, so it would help if the input could be an array)
the output would be
col1 col3
2 3
6 7
3 5
7 7
does anyone know how I might do this in bash?
【回答】
Awk或cut可以做一些较简单的文本处理，但问题稍复杂就必须用较多难懂的代码来处理。可以试一下用SPL处理，代码比较简单：
A |
|
1 |
=file("/data/file.txt").import@t(col1,col3) |
A1：读取file.txt文件中col1,col3列的数据。
读数据应该只是第一步，后面也许要进行结构化计算，比如分组汇总，排序等，可参考其他问答。
