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I've got data in a large file (280 columns wide, 7 million lines long!) and I need to swap the first two columns. I think I could do this with some kind of awk for loop, to print $2, $1, then a range to the end of the file - but I don't know how to do the range part, and I can't print $2, $1, $3...$280! Most of the column swap answers I've seen here are specific to small files with a manageable number of columns, so I need something that doesn't depend on specifying every column number.
The file is tab delimited:
Affy-id chr 0 pos NA06984 NA06985 NA06986 NA06989 
269
open(fn_in, "r", encoding) as fp_in, \ codecs. open(fn_out, "w", encoding) as fp_out: for line in fp_in: # split into two columns and rest col1, col2, rest = line. split("\t", 2) # swap columns in output fp_out.
How to switch columns in Linux. It's usually an CR-character. Meaning you have a file from the Windows/Dos world. Just run the dos2unix on that file to convert it.
The -O option of join command allows us to choose the fields to display in a particular order using which we swap the fields.
You can do this by swapping values of the first two fields:
awk ' { t = $1; $1 = $2; $2 = t; print; } ' input_file I tried the answer of perreal with cygwin on a windows system with a tab separated file. It didn't work, because the standard separator is space.
If you encounter the same problem, try this instead:
awk -F $'\t' ' { t = $1; $1 = $2; $2 = t; print; } ' OFS=$'\t' input_file Incoming separator is defined by -F $'\t' and the seperator for output by OFS=$'\t'.
awk -F $'\t' ' { t = $1; $1 = $2; $2 = t; print; } ' OFS=$'\t' input_file > output_file If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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