Re: Anagrams & Letter Banks

The %seen hash is there to remove duplicate words from the input. If a word in $key has nos been seen, then $seen{$key} will not exist and return a false value, so that we will continue the process; at the same time, the hash entry will be created for the key and the value will be 1. If the word has been seen, then $seen{$key} will exist and return a true value (1, the first time you see a duplicate word, then 2, 3...), we will go back to the top of the loop starting with the next input word.

The %word hash will have normalized words (i.e. with letters put in alphabetic orders) or signatures as keys, and for each such key, will contain an anonymous array of the original words that were translated into this signature. In other words, if an array in the hash or arrays has more than one entry, then it means that two or more words matched the normalized signature and that we have an anagram.

I hope this makes it clearer.

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Re^2: Anagrams & Letter Banks by dominick_t (Acolyte) on Oct 27, 2017 at 19:40 UTC
Thank you, Laurent_R. That definitely clears up how the %seen hash is doing its thing. The bit about the %word hash I already understood . . . It was just the use of $_ that threw me for a moment. If you have thoughts on the question asked at the beginning of the (edited) post, I'd appreciate that as well! Thanks very much for you've already written here.	[reply]
Re^3: Anagrams & Letter Banks by Laurent_R (Canon) on Oct 27, 2017 at 21:43 UTC
Basically, you have two loops in a row. In the first loop, each record is assigned to $_. When this loop is finished, $_ does not have any useful value. When you start the second loop, again, each value is assigned to $_. No problem here, but there are cases, such as nested loops, where is might become slightly dangerous (you might clobber the value of the outer $_ with the value of the inner $_); in the cases of nested loops, `while` loops and `for` don't do exactly the same thing, so it is somewhat unreliable and don't do it unless you really know what you're doing. The best, in the event of nested loops, is to use explicit variables rather than the default topical variable $_. On the questions related to your other project (not anagrams), you don't give enough details on what you need and how it is supposed to work. Please specify.	[reply] [d/l] [select]