If first two columns are equal, select top 3 based on descending order of 3rd column - linux

I want to select top 3 results for every line that has the same first two column.
For example the data will look like,
cat data.txt
A A 10
A A 1
A A 2
A A 5
A A 8
A B 1
A B 2
A C 6
A C 5
A C 10
A C 1
B A 1
B A 1
B A 2
B A 8
And for the result I want
A A 10
A A 8
A A 5
A B 2
A B 1
A C 10
A C 6
A C 5
B A 1
B A 1
B A 2
Note that some of the "groups" do not contain 3 rows.
I have tried
sort -k1,1 -k2,2 -k3,3nr data.txt | sort -u -k1,1 -k2,2 > 1.txt
comm -23 <(sort data.txt) <(sort 1.txt)| sort -k1,1 -k2,2 -k3,3nr| sort -u -k1,1 -k2,2 > 2.txt
comm -23 <(sort data.txt) <(cat 1.txt 2.txt | sort)| sort -k1,1 -k2,2 -k3,3nr| sort -u -k1,1 -k2,2 > 3.txt
It seems like it's working but since I am learning to code better was wondering if there was a better way to go about this. Plus, my code will generate many files that I will have to delete.

You can do:
$ sort -k1,1 -k2,2 -k3,3nr file | awk 'a[$1,$2]++<3'
A A 10
A A 8
A A 5
A B 2
A B 1
A C 10
A C 6
A C 5
B A 8
B A 2
B A 1
Explanation:
There are two key items to understand the awk program; associative arrays and fields.
If you reference an empty awk array element, it is an empty container -- ready for anything you put into it. You can use that as a counter.
You state If first two columns are equal...
The sort puts the file in order desired. The statement a[$1,$2] uses the values of the first two fields as a unique entry into an associative array.
You then state ...select top 3 based on descending order of 3rd column...
Once again, the sort put the file into the desired order, and the statement a[$1,$2]++ counts them. Now just count up to three.
awk is organized into blocks of condition {action} The statement a[$1,$2]++<3 is true until there are more than 3 of the same pattern seen.
A wordier version of the program would be:
awk 'a[$1,$2]++<3 {print $0}'
But the default action if the condition is true is to print $0 so it is not needed.
If you are processing text in Unix, you should get to know awk. It is the most powerful tool that POSIX guarantees you will have, and is commonly used for these tasks.
Great place to start is the online book Effective AWK Programming by Arnold D. Robbins

#Dawg has the best answer. This one will be a little lighter on memory, which probably won't be a concern for your data:
sort -k1,2 -k3,3nr file |
awk '
{key = $1 FS $2}
prev != key {prev = key; count = 1}
count <= 3 {print; count++}
'

You can sort the file by first two columns primarily and by the 3rd one numerically secondarily, then read the output and only print the first three lines for each combination of the first two columns.
sort -k1,2 -k3,3rn data.txt \
| while read c1 c2 n ; do
if [[ $c1 == $l1 && $c2 == $l2 ]] ; then
((c++))
else
c=0
fi
if (( c < 3 )) ; then
echo $c1 $c2 $n
l1=$c1
l2=$c2
fi
done

Related

Bash Colum sum over a table of variable length

Im trying to get the columsums (exept for the first one) of a tab delimited containing numbers.
To find out the number of columns an store it in a variable I use:
cols=$(awk '{print NF}' file.txt | sort -nu | tail -n 1
next I want to calculate the sum of all numbers in that column and store this in a variable again in a for loop:
for c in 2:$col
do
num=$(cat file.txt | awk '{sum+$2 ; print $0} END{print sum}'| tail -n 1
done
this
num=$(cat file.txt | awk '{sum+$($c) ; print $0} END{print sum}'| tail -n 1
on itself with a fixed numer and without variable input works find but i cannot get it to accept the for-loop variable.
Thanks for the support
p.s. It would also be fine if i could sum all columns (expept the first one) at once without the loop-trouble.
Assuming you want the sums of the individual columns,
$ cat file
1 2 3 4
5 6 7 8
9 10 11 12
$ awk '
{for (i=2; i<=NF; i++) sum[i] += $i}
END {for (i=2; i<=NF; i++) printf "%d%s", sum[i], OFS; print ""}
' file
18 21 24
In case you're not bound to awk, there's a nice tool for "command-line statistical operations" on textual files called GNU datamash.
With datamash, summing (probably the simplest operation of all) a 2nd column is as easy as:
$ datamash sum 2 < table
9
Assuming the table file holds tab-separated data like:
$ cat table
1 2 3 4
2 3 4 5
3 4 5 6
To sum all columns from 2 to n use column ranges (available in datamash 1.2):
$ n=4
$ datamash sum 2-$n < table
9 12 15
To include headers, see the --headers-out option

How to add number of identical line next to the line itself? [duplicate]

This question already has answers here:
Find duplicate lines in a file and count how many time each line was duplicated?
(7 answers)
Closed 7 years ago.
I have file file.txt which look like this
a
b
b
c
c
c
I want to know the command to which get file.txt as input and produces the output
a 1
b 2
c 3
I think uniq is the command you are looking for. The output of uniq -c is a little different from your format, but this can be fixed easily.
$ uniq -c file.txt
1 a
2 b
3 c
If you want to count the occurrences you can use uniq with -c.
If the file is not sorted you have to use sort first
$ sort file.txt | uniq -c
1 a
2 b
3 c
If you really need the line first followed by the count, swap the columns with awk
$ sort file.txt | uniq -c | awk '{ print $2 " " $1}'
a 1
b 2
c 3
You can use this awk:
awk '!seen[$0]++{ print $0, (++c) }' file
a 1
b 2
c 3
seen is an array that holds only uniq items by incrementing to 1 first time an index is populated. In the action we are printing the record and an incrementing counter.
Update: Based on comment below if intent is to get a repeat count in 2nd column then use this awk command:
awk 'seen[$0]++{} END{ for (i in seen) print i, seen[i] }' file
a 1
b 2
c 3

Find the maximum values in 2nd column for each distinct values in 1st column using Linux

I have two columns as follows
ifile.dat
1 10
3 34
1 4
3 32
5 3
2 2
4 20
3 13
4 50
1 40
2 20
What I look for is to find the maximum values in 2nd column for each 1,2,3,4,5 in 1st column.
ofile.dat
1 40
2 20
3 34
4 50
5 3
I found someone has done this using other program e.g. Get the maximum values of column B per each distinct value of column A
awk seems a prime candidate for this task. Simply traverse your input file and keep an array indexed by the first column values and storing a value of column 2 if it is larger than the currently stored value. At the end of the traversal iterate over the array to print indices and corresponding values
awk '{
if (a[$1] < $2) {
a[$1]=$2
}
} END {
for (i in a) {
print i, a[i]
}
}' ifile.dat
Now the result will not be sorted numerically on the first column but that should be easily fixable if that is required
Another way is using sort.
First numeric sort on column 2 decreasing and then remove non unique values of column 1, a one-liner:
sort -n -r -k 2 ifile.dat| sort -u -n -k 1
The easiest command to find the maximum value in the second column is something like this
sort -nrk2 data.txt | awk 'NR==1{print $2}'
When doing min/max calculations, always seed the min/max variable using the first value read:
$ cat tst.awk
!($1 in max) || $2>max[$1] { max[$1] = $2 }
END {
PROCINFO["sorted_in"] = "#ind_num_asc"
for (key in max) {
print key, max[key]
}
}
$ awk -f tst.awk file
1 40
2 20
3 34
4 50
5 3
The above uses GNU awk 4.* for PROCINFO["sorted_in"] to control output order, see http://www.gnu.org/software/gawk/manual/gawk.html#Controlling-Array-Traversal.
Considering that your 1st field will be starting from 1 if yes then try one more solution in awk also.
awk '{a[$1]=$2>a[$1]?$2:(a[$2]?a[$2]:$2);} END{for(j=1;j<=length(a);j++){if(a[j]){print j,a[j]}}}' Input_file
Adding one more way for same too here.
sort -k1 Input_file | awk 'prev != $1 && prev{print prev, val;val=prev=""} {val=val>$2?val:$2;prev=$1} END{print prev,val}'

Cat headers and renaming a column header using awk?

I've got an input file (input.txt) like this:
name value1 value2
A 3 1
B 7 4
C 2 9
E 5 2
And another file with a list of names (names.txt) like so:
B
C
Using grep -f, I can get all the lines with names "B" and "C"
grep -wFf names.txt input.txt
to get
B 7 4
C 2 9
However, I want to keep the header at the top of the output file, and also rename the column name "name" with "ID". And using grep, to keep the rows with names B and C, the output should be:
**ID** value1 value2
B 7 4
C 2 9
I'm thinking awk should be able to accomplish this, but being new to awk I'm not sure how to approach this. Help appreciated!
While it is certainly possible to do this in awk, the fastest way to solve your actual problem is to simply prepend the header you want in front of the grep output.
echo **ID** value1 value2 > Output.txt && grep -wFf names.txt input.txt >> Output.txt
Update Since the OP has multiple files, we can modify the above line to pull the first line out of the input file instead.
head -n 1 input.txt | sed 's/name/ID/' > Output.txt && grep -wFf names.txt input.txt >> Output.txt
Here is how to do it with awk
awk 'FNR==NR {a[$1];next} FNR==1 {$1="ID";print} {for (i in a) if ($1==i) print}' name input
ID value1 value2
B 7 4
C 2 9
Store the names in an array a
Then test filed #1 if it contains data in array a

In a *nix environment, how would I group columns together?

I have the following text file:
A,B,C
A,B,C
A,B,C
Is there a way, using standard *nix tools (cut, grep, awk, sed, etc), to process such a text file and get the following output:
A
A
A
B
B
B
C
C
C
You can do:
tr , \\n
and that will generate
A
B
C
A
B
C
A
B
C
which you could sort.
Unless you want to pull the first column then second then third, in which case you want something like:
awk -F, '{for(i=1;i<=NF;++i) print i, $i}' | sort -sk1 | awk '{print $2}'
To explain this, the first part generates
1 A
2 B
3 C
1 A
2 B
3 C
1 A
2 B
3 C
the second part will stably sort (so the internal order is preserved)
1 A
1 A
1 A
2 B
2 B
2 B
3 C
3 C
3 C
and the third part will strip the numbers
You could use a shell for-loop combined with cut if you know in advanced the number of columns. Here is an example using bash syntax:
for i in {1..3}; do
cut -d, -f $i file.txt
done
Try:
awk 'BEGIN {FS=","} /([A-C],)+([A-C])?/ {for (i=1;i<=NF;i++) print $i}' YOURFILE | sort

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