Awk/Unix group by - unix

Question

have this text file:
name, age
joe,42
jim,20
bob,15
mike,24
mike,15
mike,54
bob,21
Trying to get this (count):
joe 1
jim 1
bob 2
mike 3
Thanks,

Answer 1

$ awk -F, 'NR>1{arr[$1]++}END{for (a in arr) print a, arr[a]}' file.txt
joe 1
jim 1
mike 3
bob 2
EXPLANATIONS
-F, splits on ,
NR>1 treat lines after line 1
arr[$1]++ increment array arr (split with ,) with first column as key
END{} block is executed at the end of processing the file
for (a in arr) iterating over arr with a key
print a print key , arr[a] array with a key

Answer 2

Strip the header row, drop the age field, group the same names together (sort), count identical runs, output in desired format.
tail -n +2 txt.txt | cut -d',' -f 1 | sort | uniq -c | awk '{ print $2, $1 }'
output
bob 2
jim 1
joe 1
mike 3

Answer 3

It looks like you want sorted output. You could simply pipe or print into sort -nk 2:
awk -F, 'NR>1 { a[$1]++ } END { for (i in a) print i, a[i] | "sort -nk 2" }' file
Results:
jim 1
joe 1
bob 2
mike 3
However, if you have GNU awk installed, you can perform the sorting without coreutils. Here's the single process solution that will sort the array by it's values. The solution should still be quite quick. Run like:
awk -f script.awk file
Contents of script.awk:
BEGIN {
FS=","
}
NR>1 {
a[$1]++
}
END {
for (i in a) {
b[a[i],i] = i
}
n = asorti(b)
for (i=1;i<=n;i++) {
split (b[i], c, SUBSEP)
d[++x] = c[2]
}
for (j=1;j<=n;j++) {
print d[j], a[d[j]]
}
}
Results:
jim 1
joe 1
bob 2
mike 3
Alternatively, here's the one-liner:
awk -F, 'NR>1 { a[$1]++ } END { for (i in a) b[a[i],i] = i; n = asorti(b); for (i=1;i<=n;i++) { split (b[i], c, SUBSEP); d[++x] = c[2] } for (j=1;j<=n;j++) print d[j], a[d[j]] }' file

Answer 4

A strictly awk solution...
BEGIN { FS = "," }
{ ++x[$1] }
END { for(i in x) print i, x[i] }
If name, age is really in the file, you could adjust the awk program to ignore it...
BEGIN { FS = "," }
/[0-9]/ { ++x[$1] }
END { for(i in x) print i, x[i] }

Answer 5

I come up with two functions based on the answers here:
topcpu() {
top -b -n1 \
| tail -n +8 \
| awk '{ print $12, $9, $10 }' \
| awk '{ CPU[$1] += $2; MEM[$1] += $3 } END { for (k in CPU) print k, CPU[k], MEM[k] }' \
| sort -k3 -n \
| tail -n 10 \
| column -t \
| tac
}
topmem() {
top -b -n1 \
| tail -n +8 \
| awk '{ print $12, $9, $10 }' \
| awk '{ CPU[$1] += $2; MEM[$1] += $3 } END { for (k in CPU) print k, CPU[k], MEM[k] }' \
| sort -k2 -n \
| tail -n 10 \
| column -t \
| tac
}
$ topcpu
chrome 0 75.6
gnome-shell 6.2 7
mysqld 0 4.2
zsh 0 2.2
deluge-gtk 0 2.1
Xorg 0 1.6
scrcpy 0 1.6
gnome-session-b 0 0.8
systemd-journal 0 0.7
ibus-x11 6.2 0.7
$ topmem
top 12.5 0
Xorg 6.2 1.6
ibus-x11 6.2 0.7
gnome-shell 6.2 7
chrome 6.2 74.6
adb 6.2 0.1
zsh 0 2.2
xdg-permission- 0 0.2
xdg-document-po 0 0.1
xdg-desktop-por 0 0.4
enjoy!

Answer 6

cut -d',' -f 1 file.txt |
sort | uniq -c
2 bob
1 jim
1 joe
3 mike