extracting multiple consecutive columns using awk

auratus42 · January 12, 2009, 10:19pm

Hello,
I have a matrix 200*10,000 and I need to extract the columns between 40 and 77. I dont want to write in awk all the columns. eg: awk '{print $40, $41, $42,$43 ... $77}'. I think should exist a better way to do this.

pmm · January 12, 2009, 10:33pm

Have a look at - man cut

cut -d " " -f 40-77 <filename>

drl · January 12, 2009, 10:34pm

Hi.

The command cut should be useful. The syntax for selecting columns is compact ... cheers, drl

auratus42 · January 12, 2009, 10:57pm

Thanks, but 'cut' only give the first 40 columns and I want the columms after 40. I am going to check - man cut

auratus42 · January 12, 2009, 11:04pm

Sorry, the outfile only have 10 columns and each column is only "0.0000" still another 29 columns like this before the data starts in the original file.

pmm · January 12, 2009, 11:50pm

Can you give an example of the original data file - thanks

auratus42 · January 13, 2009, 12:15am

Hi, this is the first LINE, I think the problem is with the delimiter -d " ". In the original text file I have four spaces between the numbers (when I copied here shows only one space)

0.00000 0.00000

pmm · January 13, 2009, 12:38am

OK - Using nawk:

nawk ' { REC=""; for ( i = 40; i<=77; i++ ) REC=REC " " $i; print substr(REC,2) } ' <filename>

auratus42 · January 13, 2009, 1:10am

Thanks, it worked. I am going to check the - man nawk

auratus42 · January 13, 2009, 1:25am

Hello pmm,

Thanks again for your help. I am wondering what is the meaning of 'REC' in :

nawk ' { REC=""; for ( i = 40; i<=77; i++ ) REC=REC " " $i; print substr(REC,2) } ' <filename>

Cheers

pmm · January 13, 2009, 4:14pm

REC is only an internal variable used to build the string RECord.
Any variable name can be used.