Processing 2 files with different field separators using awk

Question

Let\'s say I have 2 files :

$ cat file1
A:10
B:5
C:12

$ cat file2
100 A
50 B
42 C

I\'d like to have something like :

A 10          


        

Answer 1

You can try something like:

$ cat f1
A:10
B:5
C:12

$  cat f2
100 A
50 B
42 C

$ awk 'NR==FNR{split($0,tmp,/:/);a[tmp[1]]=tmp[2];next}$2 in a{print $2,a[$2],$1}' f1 f2
A 10 100
B 5 50
C 12 42

or set multiple field separators

$ awk -F"[: ]" 'NR==FNR{a[$1]=$2;next}$2 in a{print $2,a[$2],$1}' f1 f2
A 10 100
B 5 50
C 12 42

Answer 2

Just set FS between files:

awk '...' FS=":" file1 FS=" " file2

i.e.:

$ awk 'NR==FNR{a[$1]=$2;next}{print $2,a[$2],$1}' FS=":" file1 FS=" " file2
A 10 100
B 5 50
C 12 42

Answer 3

You need to get awk to re-split $0 after you change FS.

You can do that with $0=$0 (for example).

So {FS=" ";$0=$0;...} in your final block will do what you want.

Though only doing that the first time you need to change FS will likely perform slightly better for large files.