Joining(merging) two files.

[sumittyagi]

Hi All,

I am stuck with one tricky situation here.

The situation is as follows:-
I have two files, both files have two columns - space seperated key value pairs.

Now say files are f1 and f2.
and columns in f1 are f1c1, f1c2; and columns in f2 are f2c1 and f2c2.

f2c1 is a subset of f1c1 (say keys).
f1c2 and f2c2 are different (say values).

Now I want to merge f1 and f2 into a file f3, so that f3 has three columns (space seperated):-
f1c1, f1c2, f2c2. (in DB terms I want to perform a left outer join).

I have no clue how to perform that. Can anybody assist me in this.

Thanks in advance for your valuable inputs.

Best Regards,
Sumit

[sumittyagi]

I am half way through:-

I tried to use join command, but it seems to compare in an ambiguous manner:-

Below is the sample output:-
file1 is:-

file1:-
1 51
2 52
3 53
4 54
5 55
6 56
7 57
8 58
9 59
10 60
11 61
12 62
13 63
15 65
16 66
17 67
18 68
20 70
22 72
24 74
...
...
100 150

file2 is:-

file 2:-
1 2605
2 1486
3 2783
4 2714
5 26892
6 2645
7 2838
8 84
9 143
10 26962
11 27068
12 27168
13 27250
15 27330
16 27425
17 27507
18 27594
20 27693
22 27785
24 27878
...
...
100 3291

join command gives output for one digit matches only for the key match column as shown below:-

join -j1 1 -j2 1 -o 0,1.2,2.2 -t " " file1 file2
1 51 2605
2 52 1486
3 53 2783
4 54 2714
5 55 26892
6 56 2645
7 57 2838
8 58 84
9 59 143

Note:- I don't want to use for loops to perform this task because if there are 100 rows in the files then there will be approx. 100X100 iterations, that will severely hamper the performance of the script.

[sumittyagi]

I think arrays will solve my problem...

Any other suggestions?

[sumittyagi]

Yes, arrays solved it out. it took 3 full iterations (if there are 100 elements then 3X100=300 iterations => two for assignment and one for display).

Any other improvement suggestion will be appreciated.