very fast row and column extraction 10-22-13
2014-08-29++ very fast row and column extraction 10-22-13
I talked to Sahu who knows a lot of math and programming about extracting columns from very large files. He told me he thought UNIX would be the fastest way to parse large text files. I tried it out and it is blazing fast. Just instant even with a MAPPIX aligned 128 MB 330K gpr file. Here are the two sample commands for getting the median column from a gpr file once you are in the correct directory with the command line.
awk 'NR >= 27' test.gpr>out.txt
cut -f27 out.txt>out2.txt
The first command gets the lines from line 27 to the end of the file to get rid of the header in the gpr file. The second command cuts column 27 out from the rest of the file.
see also