Mar 10 21:03:39 * Poseiden_afk is now known as Poseiden Mar 10 21:04:22 HI! Mar 10 21:04:25 hai Mar 10 21:04:28 I DID MY HOMEWORK! Mar 10 21:04:32 hai hai Mar 10 21:04:39 woohoo! Are you the mistress of hashes? Mar 10 21:04:51 No. Mar 10 21:04:54 almost Mar 10 21:04:55 I'm like, to moron of them Mar 10 21:05:00 But I kinda get them Mar 10 21:05:06 eggsalad Mar 10 21:05:11 and I kinda get confused as a baby in a topless bar with them Mar 10 21:05:19 they're like arrays but with more flexible indexes :) Mar 10 21:06:01 JulieAnn: Okay... let's get started. Mar 10 21:06:08 okay :) Mar 10 21:06:18 I printed the whole book. What page do you want me on first? Mar 10 21:06:34 JulieAnn: Book schmook. Books are for studying, not for classwork. Mar 10 21:06:40 okees. Mar 10 21:06:40 heh Mar 10 21:06:42 m'kay... hashes: Mar 10 21:06:54 * JulieAnn took notes and everything... *puts stuff away from her* Mar 10 21:06:57 #### You understand arrays? Arrays are lists, that are numerically indexed. Mar 10 21:07:39 I understand arrays. Mar 10 21:07:44 The first ones we did Mar 10 21:07:50 Good good. Mar 10 21:07:51 the slices I'm ok with I think Mar 10 21:07:59 orange slice! Mar 10 21:08:05 Okay! Excellent. Mar 10 21:08:09 it took henry a while to teach me pop/push and shift/unshift Mar 10 21:08:22 (Thankie, Henry) Mar 10 21:08:23 and nivek had a hell of a time getting me to comprehend the hash stuff. Mar 10 21:08:28 welcome Mar 10 21:08:38 it took a whopping 15 minutes for her to get it :P Mar 10 21:08:40 What's a nivek? Mar 10 21:08:53 Getting back to the hash... Mar 10 21:08:54 nivek/klb/lapjack Mar 10 21:08:55 es. Mar 10 21:09:13 Arrays are lists that are numerically indexed. Mar 10 21:09:29 Hashes are the same thing. Mar 10 21:09:32 Lists. Mar 10 21:09:46 but they can be indexed numerically, or with words Mar 10 21:09:46 The only difference is that hashes are indexed with strings, instead of with numbers. Mar 10 21:10:26 Actually, hashes are _always_ indexed with strings. They can be strings of numbers, but they are still strings. In other words, they are always the stuff that gets put in quotes. Mar 10 21:11:09 ok Mar 10 21:11:31 so...... $hash{`string'} Mar 10 21:13:50 * Disconnected (). **** ENDING LOGGING AT Sat Mar 10 21:13:50 2007 **** BEGIN LOGGING AT Sat Mar 10 21:15:27 2007 Mar 10 21:15:27 * Now talking on #perltutor Mar 10 21:15:32 damndamndamndamndamndamndamndamnndamndamn Mar 10 21:15:34 ok Mar 10 21:15:37 wb Mar 10 21:15:41 The only difference is that hashes are indexed with strings, instead of with numbers. Mar 10 21:15:41 Actually, hashes are _always_ indexed with strings. They can be strings of numbers, but they are still strings. In other words, they are always the stuff that gets put in quotes. Mar 10 21:15:41 ok Mar 10 21:15:41 so...... $hash{`string'} Mar 10 21:15:48 that's the last I had on my screen. Mar 10 21:15:52 ty henry Mar 10 21:16:14 [17:09] (so, for instance, $myhash{2 + 4} _technically_ doesn't make sense. Mar 10 21:16:14 [17:09] ) Mar 10 21:16:14 [17:10] (I say _technically_, because Perl will actually make sense of it and do something pretty close to what you expect. But _technically_ it is not Mar 10 21:16:14 a numerical index. Mar 10 21:16:14 [17:10] ) Mar 10 21:16:15 [17:11] So.. has notation. As you probably already know, hashes are referenced with a '%'. Mar 10 21:16:17 [17:12] But the hash _elements_ are still scalars (just like with arrays,) so you reference them with a '$'. Mar 10 21:16:22 [17:12] To explicitly declare a hash, you use parens just like with an array... but there are two notations for doing so. Mar 10 21:16:32 wb Mar 10 21:17:10 catching up Mar 10 21:17:13 let me reread it again Mar 10 21:17:22 JulieAnn: be careful what direction your quotes face. They must match. 'string' makes sense. `string` makes sense (for a totally different reason). `string' does not make sense in Perl. Mar 10 21:18:33 I used the same quote both times.. :/ Mar 10 21:18:36 xchat is doing pretty quotes for her Mar 10 21:18:36 '' Mar 10 21:18:43 kfoo: Ah, thanks. Mar 10 21:18:44 'string' Mar 10 21:18:53 JulieAnn: Ignore me. It's your irc client. Mar 10 21:18:59 oh, okees Mar 10 21:19:45 /bin/sh: figlet: command not found Mar 10 21:19:59 /bin/sh: -c: line 0: unexpected EOF while looking for matching `"' Mar 10 21:20:00 /bin/sh: -c: line 1: syntax error: unexpected end of file Mar 10 21:20:08 hrm. Mar 10 21:20:10 figlet rocks Mar 10 21:20:27 kfoo: Except that it's breaking. Mar 10 21:21:29 kfoo: Hrm. Apparently I uninstalled it. Oops. Mar 10 21:21:47 /bin/sh: -c: line 0: unexpected EOF while looking for matching `"' Mar 10 21:21:47 /bin/sh: -c: line 1: syntax error: unexpected end of file Mar 10 21:22:14 hrm Mar 10 21:24:55 load .ircrc Mar 10 21:24:57 grr Mar 10 21:25:17 Okay. Whew! Mar 10 21:25:35 No where were we? Ah, yes. Two ways to explicitly initialize hashes. Mar 10 21:26:35 The first notation is the normal list notation: Mar 10 21:26:52 %hash = ("word1", "word2", "word3", "word4"); Mar 10 21:27:22 ok Mar 10 21:27:37 This does _not_ do what it does with an array, however (because it can't). It does not assign each element of the list to an element of the hash. Instead, it treats the first word as a key and the second as a value. The third is a key and the fourth is its value. Mar 10 21:28:10 In other words, this notation does the same thing as: $hash{word1} = "word2"; $hash{word3} = "word4"; Mar 10 21:28:39 (Yes, hashes can be implicitly initiatlized just like arrays) Mar 10 21:29:03 Got it? Mar 10 21:29:16 erm Mar 10 21:29:20 let me read it again Mar 10 21:29:30 (sorry, it helps to reread a couple times) Mar 10 21:29:52 ok.. so... like. Mar 10 21:29:57 if I made it like Mar 10 21:31:12 %hash = ('potato', 'russet', 'candy', 'taffy') Mar 10 21:31:14 * Irinix (~Guest@pool-141-154-12-122.bos.east.verizon.net) has joined #perltutor Mar 10 21:31:17 it'd be Mar 10 21:31:57 making $hash{potato} = russet Mar 10 21:32:11 and #hash{candy} = taffy Mar 10 21:32:12 yes? Mar 10 21:32:14 poseiden, i ended up working a double today so I didn't have time to read the perl basics, and i'm gonna end up missing tonights lesson because I have to work a double tomorrow. (About to go to bed, it's 930) Mar 10 21:32:17 yup. Mar 10 21:32:34 Irinix: Sorry to hear it. You'll get all caught up, though, and the money is worth it! Mar 10 21:32:39 aye. Mar 10 21:32:44 Sorry. :( Mar 10 21:32:59 Irinix: Shit happens. Then you die. That's life in a nutshell. Mar 10 21:34:05 I'm gonna keep my log running though so I'll be able catch up. Mar 10 21:35:57 Irinix: 'kay. There will be some background stuff that we may have to cover, but you'll catch up fine. Mar 10 21:36:15 well, good night. I'll see you tomorrow night at about this time. Thanks for the confidence in my abilities Poseiden. :) Mar 10 21:36:28 Irinix: Good night. Mar 10 21:36:36 g'night Mar 10 21:37:54 my daughter is helping out tonight. there may be some somewhat.... chatic suggestions. like yugygg888 Mar 10 21:38:16 lol Mar 10 21:38:21 understood. Mar 10 21:38:37 also, this confines me to one handed keyboarding. speed will suffer. sorry. Mar 10 21:38:38 Heck, I might understand HER explanations better than yours. Yanno, she's more on my level Mar 10 21:38:39 ;) Mar 10 21:38:45 :P Mar 10 21:40:20 okay, you have the first explicit notation. the second is similar, but more clear. It is "key => value", as in: %hash = ( "word1" => "word2", "word3" => "word4"); Mar 10 21:40:41 Make sense? Mar 10 21:41:23 yeah, I get that. Mar 10 21:41:34 That's how nivek tried explaining it the first time heh Mar 10 21:41:48 Okay. Now your first style point (we'll have plenty more): Always use the second form. Mar 10 21:42:49 The first form, ("key", "value", "key2", "value2"), is hard to figure out. Don't use it. It is a good thing that Perl understands this notation, but that doesn't mean you should ever, ever use it in your own code (as you'll see, its value comes elsewhere). Mar 10 21:43:20 ok. Mar 10 21:43:20 Got it? Mar 10 21:43:22 Got it :) Mar 10 21:43:23 Great. Mar 10 21:43:43 Okay... a bit of cleanup: I forgot to tell you about undef. Mar 10 21:44:03 Scalar variables don't always have values (often because you screw up). For instance, consider the following code: Mar 10 21:44:14 #!/usr/bin/perl Mar 10 21:44:44 if ($dog eq 'retriever') { print "Hiya, Goldie!\n"; } Mar 10 21:44:51 What's the problem there? Mar 10 21:45:10 ummmm Mar 10 21:45:46 I dunno... Mar 10 21:45:48 :/ Mar 10 21:45:56 what is $dog set to? Mar 10 21:46:09 retriever Mar 10 21:46:13 Nope. Mar 10 21:46:18 ? Mar 10 21:46:21 oh Mar 10 21:46:22 wait Mar 10 21:46:25 it's set to Mar 10 21:46:26 There is no assignment there - look again (it's a comparison). Mar 10 21:46:27 Mar 10 21:46:29 or something Mar 10 21:46:37 ok. Mar 10 21:46:41 where is it set to ? Mar 10 21:46:57 It's not.. not just from that one line of code Mar 10 21:47:09 JulieAnn: Right. Mar 10 21:47:16 I was trying to guess Mar 10 21:47:17 :/ Mar 10 21:47:28 It is totally unset. Perl has no idea what $dog might be. Mar 10 21:48:12 shih tzu! Mar 10 21:48:16 possibly. Mar 10 21:48:29 sorry, i thought I was supposed to like, know. Mar 10 21:48:30 (Notice that there are two lines - the shebang, which _must_ be the very first line of your Perl program if it is there at all, and then the branch. Since $dog wasn't set in that space, you can know for certain that $dog is unset at the time of the comparison). Mar 10 21:48:30 :/ Mar 10 21:48:46 ok Mar 10 21:49:12 JulieAnn: np. The point is that $dog is unset. Perl has no idea what its value should be. We are comparing a variable with no declared value to a fixed string. Mar 10 21:49:22 Ok. Mar 10 21:49:44 there is no dog :\ Mar 10 21:50:43 Whenever a variable is created, Perl gives that variable an initial value. The value _looks like_ the empty string ("") when it is compared to a string, and looks like 0 when it is compared to a number. It looks like 'false' when it is compared to a boolean value. But it is not "", 0, or false. Mar 10 21:51:05 Instead, it is undef. That is a Perl keyword, meaning, literally, "having no value". Mar 10 21:51:22 undefined? Mar 10 21:52:13 That's right. It's actually an unfortunate choice, because mathematicians think that "7/0" is "undefined." That word has an intrinsic meaning that is different from the Perl meaning. Mar 10 21:52:49 7/0 is defined on certain pentium chips .. Mar 10 21:53:01 oh, ok... Mar 10 21:53:21 But, anyhow, the moral of the story is that there is a secret neato value of undef. You can test for undef. We'll get into that later. Mar 10 21:53:28 ok Mar 10 21:53:49 Back to hashes. As you've already seen, the index of a hash is in curly braces: {}. Mar 10 21:53:57 yes Mar 10 21:54:07 The index is also called the "key". It is the "key" that corresponds to the value of the hash element. Mar 10 21:55:04 Hashes have some absolutely outstanding properties. One big one is that assignment to $hash{four} (or even $hash{"4"} for that matter) does _not_ imply that there is a $hash{three}. Mar 10 21:55:29 This is different from arrays. Consider: Mar 10 21:55:33 #!/usr/bin/bash Mar 10 21:55:42 $array[4] = 7; Mar 10 21:55:51 $hash["4"] = 7; Mar 10 21:56:12 How many _scalars_ will Perl create (and reserve memory and other overhead for)? Mar 10 21:56:37 3 Mar 10 21:56:39 4 Mar 10 21:56:43 0-3 Mar 10 21:56:52 0, 1, 2, 3 Mar 10 21:57:14 for the array, 0, 1, 2, 4 Mar 10 21:57:17 Right spirit. Remember the two that get created explicitly. Mar 10 21:57:51 (One is an array element, the other is a hash element) Mar 10 21:57:51 so 5? Mar 10 21:58:15 or 8? Mar 10 21:58:26 Six, altogether. $array[0], $array[1], $array[2], $array[3], $array[4], and $hash{"4"}. Mar 10 21:58:29 Because you said just because there is a 4, doesn't mean there's a 3. Mar 10 21:58:56 :/ Mar 10 21:58:57 ok Mar 10 21:59:04 Does that make sense? Mar 10 21:59:35 yes Mar 10 21:59:57 Okay. Mar 10 22:00:01 I wasn't counting $array[4] for some reason Mar 10 22:00:12 Now you'll see why the _first_ form of hash initialization is useful. Mar 10 22:00:40 the one I should never use? Mar 10 22:00:52 Write a program that creates and initializes a hash with 10 key/value pairs. Mar 10 22:01:13 Then have your program 'print %myHash; print "\n";' Mar 10 22:01:17 ok Mar 10 22:01:25 JulieAnn: Right, the one you should never, ever use. Mar 10 22:01:38 (You'll secretly use it all the time, but it'll be under cover of darkness). Mar 10 22:02:03 You want me to do this with the first method, right? Mar 10 22:02:13 No. NEVER use the first method. Mar 10 22:02:16 the forbidden method :P Mar 10 22:02:28 so you want me to use the 2nd method to do it? Mar 10 22:02:33 JulieAnn: That's right. Mar 10 22:02:35 ok. Mar 10 22:07:39 ok Mar 10 22:07:45 Works? Mar 10 22:07:51 it printed them all in one big long string Mar 10 22:08:11 Excellent! Now do the same thing, but with an array instead of a hash. Mar 10 22:08:56 ok. Mar 10 22:10:06 My style is da bomb de bomb de dang di dang diggy diggy Mar 10 22:10:19 Poseiden: ignore me if this is jumping ahead, but what do the numbers represent when you print a hash in scalar context? Mar 10 22:10:52 kfoo: Same thing they do in any list - the length of the list. Mar 10 22:10:58 8/16 ? Mar 10 22:11:10 kfoo: ?? I've not seen that. What perl are you using? Mar 10 22:11:20 5.8.8 Mar 10 22:11:25 it said I have a bad name Mar 10 22:11:26 kfoo: code? Mar 10 22:11:40 JulieAnn: cover your eyes Mar 10 22:11:45 my %hash = qw(one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty); Mar 10 22:11:46 JulieAnn: Well I disagree with that. You have a fine name! Just fine. Tell it to @#@#%@ off. Mar 10 22:11:48 print %hash."\n"; Mar 10 22:12:10 kfoo: HRM! No idea. It should print 20. Mar 10 22:12:24 i figured it out Mar 10 22:12:30 kfoo: I must be wrong about something. I'll look it up. Mar 10 22:13:06 julieann@WhimsicalAgony:~$ ./array.pl Mar 10 22:13:06 Bad name after lemonade' at ./array.pl line 3. Mar 10 22:13:10 it said that cuz I forgot a ' Mar 10 22:15:53 kfoo: HRM! Mar 10 22:16:00 Poseiden: buckets Mar 10 22:16:07 kfoo: curiously, it says the same thing to me. Mar 10 22:16:27 kfoo: shouldn't be buckets. Mar 10 22:16:33 its buckets Mar 10 22:16:44 kfoo: I believe you that it is, but it shouldn't be. Mar 10 22:17:04 kfoo: Let's figure that out. Mar 10 22:17:08 kfoo: later. Mar 10 22:17:19 JulieAnn: Okay, so what did you get for output? Mar 10 22:17:37 julieann@WhimsicalAgony:~$ ./array.pl Mar 10 22:17:37 (peanut phone camel candy lemonade lipgloss purse lighter pencil kfoo) Mar 10 22:17:37 julieann@WhimsicalAgony:~$ Mar 10 22:17:52 just used things that are on my bed heh Mar 10 22:18:03 JulieAnn: code? Mar 10 22:18:17 #!/usr/bin/perl Mar 10 22:18:17 @array = ('peanut', 'phone', 'camel', 'candy', 'lemonade', 'lipgloss', Mar 10 22:18:17 'purse', 'lighter', 'pencil', 'kfoo'); Mar 10 22:18:17 print "(@array)"; Mar 10 22:18:17 print "\n"; Mar 10 22:18:38 JulieAnn: kay. Mar 10 22:18:50 JulieAnn: Code for your hash proggie? Mar 10 22:19:12 #!/usr/bin/perl Mar 10 22:19:12 %hash = ('pepper' => 'cat', 'fish' => 'guppy', 'nut' => 'cashew', Mar 10 22:19:12 'teacher' => 'Poseiden', 'splendiferous' => 'kfoo', 'asshole' => 'nick', Mar 10 22:19:12 'student' => 'julieann', 'cigarettes' => 'trash', 'soda' => 'dietcoke', Mar 10 22:19:12 'food' => 'ribs'); Mar 10 22:19:12 print %hash; Mar 10 22:19:12 print "\n"; Mar 10 22:20:26 JulieAnn: Alright. Make the print statements comparable - either put both in quotes or neither. Mar 10 22:20:41 oh. Mar 10 22:20:45 I'm sorry :( Mar 10 22:21:28 JulieAnn: np. Actually, don't put them in quotes. List interpolation in quotes stinks. Mar 10 22:22:16 julieann@WhimsicalAgony:~$ ./hash.pl Mar 10 22:22:16 assholenicksplendiferouskfoocigarettestrashpeppercatsodadietcokefishguppyfoodribsnutcashewstudentjulieannteacherPoseidenSCALAR(0x8149768)julieann@WhimsicalAgony:~$ Mar 10 22:22:19 that's the output Mar 10 22:23:11 Okay. Two important things to notice. Mar 10 22:24:05 One - everything prints in key/value pairs. Read it: "assholenick" corresponds to 'asshole' => 'nick'. "splendiforouskfoo" == "splendiforous" => "kfoo". Etc. Mar 10 22:24:19 yar Mar 10 22:24:22 heh Mar 10 22:24:25 Two - it is in a totally different order than the order in which you did the assignments. Mar 10 22:24:46 brb Mar 10 22:25:39 right Mar 10 22:28:23 Okay, back. Mar 10 22:28:28 wb :D Mar 10 22:28:28 left Mar 10 22:28:43 Now there is one more thing to note in addition. Mar 10 22:29:42 ok Mar 10 22:29:44 That is - it looks like the same glop of @#$ that drops out when you print arrays. Mar 10 22:30:00 mmhmm Mar 10 22:31:24 the moral of that particular story is that in list mode, a hash is just a list. And it is a list, in no particular order, of strings that are paired key value key value key value ... Mar 10 22:32:02 unless its a tied hash.. Mar 10 22:32:07 This makes it easy to assign hashes to other hashes (ta-da! The magic of the forbidden explicit initialization). Mar 10 22:32:12 kfoo: grrrrr Mar 10 22:32:24 ignore that :D Mar 10 22:32:41 Think about: %hash2 = %hash1; Mar 10 22:33:04 ok Mar 10 22:33:07 When %hash1 dumps out, it'll be a list. Mar 10 22:33:28 Because of the magic forbidden method, that list will assign to %hash2. Mar 10 22:33:49 ok Mar 10 22:33:55 This will make every key in %hash1 into a key in %hash2, and will make every value in %hash2 correspond to the key that has the same value in %hash1. Mar 10 22:34:16 See? Works just you might expect. Mar 10 22:34:35 Also, this property of hashes allows you to switch between hashes and arrays at will: Mar 10 22:34:38 :) Mar 10 22:34:47 %hash = @array; will do something useful. Mar 10 22:35:16 thats good for feeding in arguments to functions.. Mar 10 22:35:21 It also means you can do things that might look useless, but are actually incredibly powerful: Mar 10 22:35:43 %hash2 = reverse %hash1;, for instance. Very valuable. Mar 10 22:36:16 hm yeah. i never realized that Mar 10 22:36:20 Why is that so valuable? Because it is easy (and fast) to count the number of elements in a hash, and each hash key can correspond to only one hash value. Mar 10 22:36:48 So %hash2 = reverse %hash1 gives you an almost instant way to count the number of unique values in %hash1. Mar 10 22:37:09 (Think it through - take it apart slowly - and this will make sense to you). Mar 10 22:37:56 ah Mar 10 22:37:59 * kfoo just learned something Mar 10 22:38:51 JulieAnn: Making any sense? Mar 10 22:38:56 Yes. Mar 10 22:39:01 JulieAnn: Cool! Mar 10 22:39:09 you understand why it will give you only unique values? Mar 10 22:39:15 hold on Mar 10 22:39:18 it's making sense. Mar 10 22:39:23 I didn't say it MADE sense Mar 10 22:39:25 yet Mar 10 22:39:38 :) Fair enough. Mar 10 22:39:43 henry... I need oral. Mar 10 22:39:45 Dinner soon. Mar 10 22:39:48 verbal Mar 10 22:39:49 not oral Mar 10 22:39:52 shit that sounded bad Mar 10 22:39:57 * kfoo blinks Mar 10 22:40:00 "Henry, I need oral." Oh to be young. Mar 10 22:40:10 no.. I meant oral dictation Mar 10 22:40:14 verbal explanation Mar 10 22:40:18 Don't we all? Mar 10 22:40:26 is it bad that that helps me sometimes? :/ Mar 10 22:40:42 Nope! That's good. Or, more accurately, it is good that you know that that helps. Mar 10 22:40:55 i read all of this stuff outloud Mar 10 22:40:59 henry heard me earlier heh Mar 10 22:41:14 Nick;s mom is like "What are you talking to in there?" I said "A piece of paper :/" Mar 10 22:41:17 * Poseiden often wishes he knew what would help him grasp those things that are obscure to him now. Like the female psyche. Mar 10 22:41:43 you mean obscure, or impossible? :) Mar 10 22:41:52 :/ Mar 10 22:41:57 kfoo: shit. I hoped it was merely obscure. Mar 10 22:42:01 Maybe I'm just not a female. Mar 10 22:42:10 yes, you are Mar 10 22:42:29 I'm not hard to understand though Mar 10 22:42:34 I just don't understand things Mar 10 22:42:55 Okay, dinner is served. You two figure out the reverse hash thing? And we'll get into hash functions after supper? Mar 10 22:43:20 sounds good. Mar 10 22:43:26 cheers. bbl. Mar 10 22:43:28 Henry's connection just died. He'll be back in a few Mar 10 22:49:38 bleh Mar 10 22:59:32 bleh blah blooey Mar 10 23:00:05 Okay. Good dinner. Understand reverse hash? Mar 10 23:00:16 think so, making her write an example program Mar 10 23:00:18 If not, no biggie - we'll move into hash functions. Mar 10 23:00:41 Cool. JulieAnn, keep working on that. I'm going to go into hash functions a bit, and you can scroll it and read at your leisure. Mar 10 23:00:54 4pink1red3blue2blueSCALAR(0x81496fc)pink4blue3red1SCALAR(0x8149708)julieann@WhimsicalAgony:~$ Mar 10 23:01:06 There are only three important functions that are specific to hashes that I care about at the moment. Mar 10 23:01:23 #!/usr/bin/perl Mar 10 23:01:23 %hash = ("1" => "red", "2" => "blue", "3" => "blue", "4" => "pink"); Mar 10 23:01:23 print %hash; Mar 10 23:01:23 print \n; Mar 10 23:01:23 %hash2 = reverse %hash; Mar 10 23:01:23 print %hash2; Mar 10 23:01:23 print \n; Mar 10 23:03:40 julieann@WhimsicalAgony:~$ ./print.pl Mar 10 23:03:40 4pink1red3blue2blue Mar 10 23:03:40 pink4blue3red1 Mar 10 23:03:40 julieann@WhimsicalAgony:~$ Mar 10 23:03:42 better Mar 10 23:04:10 Cool. Looks like you've got it. Mar 10 23:04:13 :D Mar 10 23:04:15 so it looks like the 2nd value and so on gets dropped Mar 10 23:04:25 kfoo: You can't actually depend on that. Mar 10 23:04:35 kfoo: Some value will get dropped. Not clear which one. Mar 10 23:04:38 yeah Mar 10 23:05:12 Alright, our three functions. The first is keys(). keys() just lists all of the keys of the hash. Mar 10 23:06:10 values() lists the values! Mar 10 23:06:23 Try it: perl -e '%hash={"hello"=>"world","my heart"=>"San Francisco"); print keys %hash; print "\n";' Mar 10 23:06:28 JulieAnn: Two down. :) Mar 10 23:06:41 Poseiden, it took nivek an hour to explain that. :( Mar 10 23:06:44 when do we get to references? heh Mar 10 23:06:48 The third one is 'delete'. Mar 10 23:06:50 because i wasnt grasping what was what Mar 10 23:06:52 kfoo: not soon. :P Mar 10 23:07:08 Well you've clearly got it now. :) Mar 10 23:07:39 :D Mar 10 23:07:49 Delete removes an element from the hash. $hash{foo}="bar"; delete $hash{foo};. Mar 10 23:08:00 that's simple enough Mar 10 23:08:27 There is one more hash-specific function. It is actually unnecessary, but extremely efficient. Mar 10 23:08:47 The each() function returns the next key/value pair in the hash. Mar 10 23:09:07 So, for instance: Mar 10 23:09:49 while ( ($key,$value) = each(%hash) ) { print "The value for key " . $key ." is ". $value .".\n"; } Mar 10 23:10:22 Do you understand that loop? Mar 10 23:10:28 I think Mar 10 23:10:38