Property Lists!
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From: Garek007 on 18 Oct 2006 19:49 Hi, I am trying to use a property list in my Director and because of this, I cannot save or run my movie. Here is an example. I have a function that runs on movie start and reads a text file putting the elements into a property list. Later in the move I try to read from this list with x = myList["2280"] But because the list isn't created until the movie starts and runs my function getData() the movie won't let me start? It tells me variable used before assigned a value, but if the movie would just start it WOULD have a value! What can I do? Thanks, Stan
From: Chunick on 18 Oct 2006 22:51 Have you tested to see if the function is called and the variable containing the property list is properly created?... My frist guess would be that you haven't set the variable to be global. If you are not familiar with variable scope then press F1 to bring up the help window and in the search tap type in "scope" (without quotes) and you should see an entry named "Variables" click on that and that should give you a clear explanation. The second thing I see is that myList["2280"] means that you are assigning the value of the property "2280" to x. This seems to be a wasteful use of property lists because your property name "2280" doesn't seem to have any significance and if it refers to the position of the entry in the property list then it's redundant. For example: a property list: pList = ["1": 3334, "2": 12, "3": 87, "4": 9008] put pList["4"] -- 9008 a list: aList = [3334, 12, 87, 9008] put aList[4] -- 9008 There's little to no benefit in that example to use a property list over a plain list. However, if the properties had meaning like this: property list: pHighScoreList = ["Jack": 3334, "LZR": 12, "Sub Zero": 87, "ACE": 9008] put pHighScoreList["ACE"] -- 9008 then we have a good use for property lists over plain lists because I can now get the high score for a particular individual by using that person's name they entered.
From: duckets on 19 Oct 2006 06:43 is 'myList' supposed to be a global? if so, maybe you forgot to put: "global myList" at the top of your script which is causing the error. The error "variable used before assigned a value" can be slightly misleading, because you don't actually have to assign it a value. You just have to declare that it's a property or a global. It then has a value of 'void', which is technically 'unnassigned', but your code should now work, hopet this helps, - Ben
From: the real POTMO on 19 Oct 2006 09:46 there are actually two types of lists. Linear lists and property lists. the linear list can be accessed by using its index myList = ["yeah", "wow", "fresh"] put myList[2] --wow the propertyList can be accessed by using index or key. myList = ["propone" : "yeah", "proptwo" : "wow", "helloworld" : "fresh"] put = myList[2] -- wow put = myList["propone"] --yeah you can also use symbols as keys ("I think its a bit quicker") myList = [#propone : "yeah", #proptwo : "wow", #helloworld : "fresh"] put myList[#propone] --yeah or with dot syntax put myList.propone --yeah if you use dot syntax and the key does not exist youll get an error. if you use [] syntax youll get void as result with keys not existing. myList = [#propone : "yeah", #proptwo : "wow", #helloworld : "fresh"] also you can write myList[#somenewprop] = "woha" if the key does not exits it will add it and the value. put myList --[#propone : "yeah", #proptwo : "wow", #helloworld : "fresh", #somenewprop:"woha"] remember if you use strings as keys the keys are case sensitive "propOne" <> "propone" if you use symbols as keys you cant have a number as first char in the key #1223key = BAD #key1223 = GOOD if you use strings as keys its ok to have numbers as first chars or numbers only like "1223key" = OK so the soultion to yor problem: i think youre accessing the list with x = myList["2280"] instead of x= myList[2280] a bit of a overkill help but it might help someone
From: Garek007 on 19 Oct 2006 13:19
POTMO, 2280 is actually a string not a reference to a position in the list, so it should still be "2280" no? Chunick, Maybe I could use a regular list, it would be a hell of a lot easier. Here's what I am trying to do, please tell me what would work best. I have an excel file that I exported to a tab delimited text file. In essence it's a table of values. I need to be able to read those values in and call them up at will. It seems like a property list would make that easier because I can have each line referenced as a category and then call items in that line using the first word of that line, in this case "2280". Am I overcomlicating this? |