Subroutine to check word presence

Hello there, I'm quite new to using Perl and I still have a lot to learn. Would be nice if you could help me on that one.

I handle dictionary data and I have to write a script that checks if words in data corpus exists or not in a word-list file. If it exists, it has to do nothing but if it doesn't, I want it to print that word.

The point is, I have to NOT use hashes or grep to look for the presence. So here comes subroutine (or so I think, but if you have better advice, I'm all ears).

So first, I open the word-list file (one word per line format), I push each word in an array and close the file. Then I use sort to sort alphabetically the array.

I then open the corpus data (also one word per line), and it's there that I'm stuck. If using subroutine, I know I have to use cmp to do a binary search, but I don't know at all how you can write it to compare each readen word of the corpus data with the word-list data. How should it be written ?

Any help is welcome

Why the restrictions: no hash or grep? Is this school work?

I'm studying perl at work, and already having learnt about hashes and arrays, the guy teaching me perl wants me to do it with something else (subroutines ?).

If you are using perl 5.10, you can use smart matching, which is really cool. Otherwise, you can use a foreach loop on the array for every line of the file, in consideration of the restrictions placed on you.

Thank you for your help. First time I heard about smart matching. I googled it and it seems quite effective.



Ok, some questions about this. Wouldn't you then need to use grep on this ? I'm still learning so I may not understand really how you mean this. Another problem is that the file is quite huge (~100000 lines) so it would take a lot of time with foreach, or do I understand this wrong ?

Anyway, thanks a lot for your help.

I thought one of the constraints was that you couldn't use grep.

I would rather use a hash, but I was thinking along the lines of

Well, I can't use grep, but your code seems good too. Thank you, I'll give it a try !

Ok, back I am. It seems like the perl version we use at work is outdated, so no sweet smart-matching for me.

Also, keath, (tell me if I'm wrong, but) your code prints only if the read word EXISTS in the array, but I have to print only what doesn't exist in the array. Without hashes and grep, I'm such a sucker

Any help ?

Check the whole array first before drawing a conclusion and printing the word. Create a flag variable. Set it in the loop if there's a match, then check at the end and see if the flag was set. If it wasn't set, print.

But I have to say that the exercise of trying to solve a problem using perl, but not allowing one to use the features of that language, seems pointless. I would rather someone taught me the language, rather than teach me how to use the language in an imaginary world where it didn't have certain features.

Thanks for your help, keath.



So true...