问题
I want to print a particular column (in this case column 7) of my file in scientific notation, whereas rest of the columns get printed as is.
How can I selectively use printf only for column 7 and just print for first 6 columns?
example input:
C 6 12.011 0.51 3.56E-01 4.60E-01 0.458399
CA 6 12.011 -0.15 3.55E-01 2.93E-01 0.291708
CAI 6 12.011 -0.25 3.55E-01 3.05E-01 0.30421
CC 6 12.011 0.62 3.56E-01 2.93E-01 0.291708
desired output:
C 6 12.011 0.51 3.56E-01 4.60E-01 4.58E-01
CA 6 12.011 -0.15 3.55E-01 2.93E-01 2.92E-01
CAI 6 12.011 -0.25 3.55E-01 3.05E-01 3.04E-01
CC 6 12.011 0.62 3.56E-01 2.93E-01 2.92E-01
回答1:
You can use sprintf:
$ awk -v OFS="\t" '{ $7 = sprintf("%.2E", $7) }1' input.txt
C 6 12.011 0.51 3.56E-01 4.60E-01 4.58E-01
CA 6 12.011 -0.15 3.55E-01 2.93E-01 2.92E-01
CAI 6 12.011 -0.25 3.55E-01 3.05E-01 3.04E-01
CC 6 12.011 0.62 3.56E-01 2.93E-01 2.92E-01
回答2:
To change only the last column without affecting spacing of other fields:
$ cat ip.txt
C 6 12.011 0.51 3.56E-01 4.60E-01 0.458399
CA 6 12.011 -0.15 3.55E-01 2.93E-01 0.291708
CAI 6 12.011 -0.25 3.55E-01 3.05E-01 0.30421
CC 6 12.011 0.62 3.56E-01 2.93E-01 0.291708
$ perl -pe 's/\S+$/sprintf "%.2E", $&/e' ip.txt
C 6 12.011 0.51 3.56E-01 4.60E-01 4.58E-01
CA 6 12.011 -0.15 3.55E-01 2.93E-01 2.92E-01
CAI 6 12.011 -0.25 3.55E-01 3.05E-01 3.04E-01
CC 6 12.011 0.62 3.56E-01 2.93E-01 2.92E-01
If some other column is required:
$ perl -pe 's/^(\S+\s+){2}\K\S+/sprintf "%.2E", $&/e' ip.txt
C 6 1.20E+01 0.51 3.56E-01 4.60E-01 0.458399
CA 6 1.20E+01 -0.15 3.55E-01 2.93E-01 0.291708
CAI 6 1.20E+01 -0.25 3.55E-01 3.05E-01 0.30421
CC 6 1.20E+01 0.62 3.56E-01 2.93E-01 0.291708
来源：https://stackoverflow.com/questions/39577287/awk-printf-a-particular-column-in-a-file