Awk Array doesnt match for substring

Shell Programming and Scripting
1

Awk Array doesnt match for substring

nawk -F"," 'FNR==NR{a[$1]=$2 OFS $3;next} a[$2]{print $1,$2,a[$2]}' OFS="," file1 file2

I want cluster3 in file1 to match with cluster3int in file2
output getting:

Output required:

Help is appreciated

2

where's 'cluster3int' in file1??

3

'cluster3int' is not in file1 but i want the code to match with substring.

cluster3 exists in file2 which is substring of cluster3int from file1 .
I want to match cluster3 from file2 with 'cluster3int' which exists in file1

Appreciate help

Thanks

4

Also, 'cluster2' exists in file2. And 'cluster2' is a 'substring' of 'cluster2' and 'xyz.cluster2' from file1.
What's the algorithm?

5

basically the file1 will have incomplete names on the trailing side from entries in file2.

So if
xyz.cluster2 in file2
can match only with

xyz.clust
or
xyz.cluste
or
xyz.clus

---------------------------------------------------------
'xyz.cluster2' in file2 ,
cluster2 in file1 has no "xyz" in leading side so its a different entry.

Hope this clarifies the requirement

6 
nawk -F"," 'FNR==NR{a["^" $1]=$2 OFS $3;next} {for (i in a) if ($2 ~ i) { print $1,$2,a;next}}' OFS="," file1 file2

Now... could you please explain it how it works - step by step with code comments.

7

Thanks vgersh99
Here is the explanation

nawk -F"," 'FNR==NR{a["^" $1]=$2 OFS $3;next} {for (i in a) if ($2 ~ i) { print $1,$2,a;next}}' OFS="," file1 file2

FNR==NR

Checking for first file i.e file1

a["^" $1]=$2 OFS $3;next}

Creating array for first field of file1 with "^" appended to it
so array will be like
a[^cluster1]
a[^cluster2]
a[^cluster3]

next

the remaining code after next statement is not executed when awk is processing first file file1

{for (i in a) if ($2 ~ i) { print $1,$2,a;next}}

for (i in a)

looping through each element of array using awk special for loop

if ($2 ~ i)

checking for second field of file2 in each array index.
if found
print $1,$2,a[i];next

print $1,$2,a

prints column 1 and 2 from file2 and array content

next

this is not needed.But doesnt hurt as well.

OFS=","

output field seperator is comma

8

Very well - you seem to understand the solution.
Good luck in the future.

9

This may work.

awk -F, 'BEGIN {i=0
while ((getline < "file2") > 0)
{i++
file2=$0 }
imax=i
}
{
  for (i in file2)
  {
   if ($1 == substr(file2,5,length($1)))
   {
     file2loc=sprintf("%s,%s", $2, $3)
   }
  }
}
END {
  for (i=1;i<=imax;i++)
      print file2 "," file2loc
}'

file1