awk or shell command to count occurence of value in 1st column based on values in 4th column - bash

Question

I have a large file with records like below :
jon,1,2,apple
jon,1,2,oranges
jon,1,2,pineaaple
fred,1,2,apple
tom,1,2,apple
tom,1,2,oranges
mary,1,2,apple
I want to find the no of person (names in col 1) have apple and oranges both. And the command should take as less memory as possible and should be fast. Any help appreciated!
Output :
awk/sed file => 2 (jon and tom)

Answer 1

Using awk is pretty easy:
awk -F, \
'$4 == "apple" { apple[$1]++ }
$4 == "oranges" { orange[$1]++ }
END { for (name in apple) if (orange[name]) print name }' data
It produces the required output on the sample data file:
jon
tom
Yes, you could squish all the code onto a single line, and shorten the names, and otherwise obfuscate the code.
Another way to do this avoids the END block:
awk -F, \
'$4 == "apple" { if (apple[$1]++ == 0 && orange[$1]) print $1 }
$4 == "oranges" { if (orange[$1]++ == 0 && apple[$1]) print $1 }' data
When it encounters an apple entry for the first time for a given name, it checks to see if the name also (already) has an entry for oranges and prints it if it has; likewise and symmetrically, if it encounters an orange entry for the first time for a given name, it checks to see if the name also has an entry for apple and prints it if it has.
As noted by Sundeep in a comment, it could use in:
awk -F, \
'$4 == "apple" { if (apple[$1]++ == 0 && $1 in orange) print $1 }
$4 == "oranges" { if (orange[$1]++ == 0 && $1 in apple) print $1 }' data
The first answer could also use in in the END loop.
Note that all these solutions could be embedded in a script that would accept data from standard input (a pipe or a redirected file) — they have no need to read the input file twice. You'd replace data with "$#" to process file names if they're given, or standard input if no file names are specified. This flexibility is worth preserving when possible.

Answer 2

With awk
$ awk -F, 'NR==FNR{if($NF=="apple") a[$1]; next}
$NF=="oranges" && ($1 in a){print $1}' ip.txt ip.txt
jon
tom
This processes the input twice
In first pass, add key to an array if last field is apple (-F, would set , as input field separator)
In second pass, check if last field is oranges and if first field is a key of array a
To print only number of matches:
$ awk -F, 'NR==FNR{if($NF=="apple") a[$1]; next}
$NF=="oranges" && ($1 in a){c++} END{print c}' ip.txt ip.txt
2
Further reading: idiomatic awk for details on two file processing and awk idioms

Answer 3

I did a work around and used only grep and comm commands.
grep "apple" file | cut -d"," -f1 | sort > file1
grep "orange" file | cut -d"," -f1 | sort > file2
comm -12 file1 file2 > names.having.both.apple&orange
comm -12 shows only the common names between the 2 files.
Solution from Jonathan also worked.

Answer 4

For the input:
jon,1,2,apple
jon,1,2,oranges
jon,1,2,pineaaple
fred,1,2,apple
tom,1,2,apple
tom,1,2,oranges
mary,1,2,apple
the command:
sed -n "/apple\|oranges/p" inputfile | cut -d"," -f1 | uniq -d
will output a list of people with both apples and oranges:
jon
tom
Edit after comment: For an for input file where lines are not ordered by 1st column and where each person can have two or more repeated fruits, like:
jon,1,2,apple
fred,1,2,apple
fred,1,2,apple
jon,1,2,oranges
jon,1,2,pineaaple
jon,1,2,oranges
tom,1,2,apple
mary,1,2,apple
tom,1,2,oranges
This command will work:
sed -n "/\(apple\|oranges\)$/ s/,.*,/,/p" inputfile | sort -u | cut -d, -f1 | uniq -d