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  • Best way to implement a List(Of) with a maximum number of items

    - by Ben
    I'm trying to figure out a good way of implementing a List(Of) that holds a maximum number of records. e.g. I have a List(Of Int32) - it's being populated every 2 seconds with a new Int32 item. I want to store only the most current 2000 items. How can I make the list hold a maximum of 2000 items, then when the 2001'th item is attempted to be added, the List drops the 2000'th item (resulting in the current total being 1999). Thing is, I need to make sure I'm dropping only the oldest item and adding a new item into the List. Ben

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  • Using a Loop to add objects to a list(python)

    - by Will
    Hey guys so im trying to use a while loop to add objects to a list. Heres bascially what i want to do: (ill paste actually go after) class x: blah blah choice = raw_input(pick what you want to do) while(choice!=0): if(choice==1): Enter in info for the class: append object to list (A) if(choice==2): print out length of list(A) if(choice==0): break ((((other options)))) as im doing this i can get the object to get added to the list, but i am stuck as to how to add multiple objects to the list in the loop. Here is my actual code i have so far... print "Welcome to the Student Management Program" class Student: def init (self, name, age, gender, favclass): self.name = name self.age = age self.gender = gender self.fac = favclass choice = int(raw_input("Make a Choice: " )) while (choice !=0): if (guess==1): print("STUDENT") namer = raw_input("Enter Name: ") ager = raw_input("Enter Age: ") sexer = raw_input("Enter Sex: ") faver = raw_input("Enter Fav: ") elif(guess==2): print "TESTING LINE" elif(guess==3): print(len(a)) guess=int(raw_input("Make a Choice: ")) s = Student(namer, ager, sexer, faver) a =[]; a.append(s) raw_input("Press enter to exit") any help would be greatly appreciated!

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  • Idiomatic scheme and generic programming, why only on numbers ?

    - by Skeptic
    Hi, In Scheme, procedures like +, -, *, / works on different types of numbers, but we don't much see any other generic procedures. For example, length works only on list so that vector-length and string-length are needed. I guess it comes from the fact that the language doesn't really offer any mechanism for defining generic procedure (except cond of course) like "type classes" in Haskell or a standardized object system. Is there an idiomatic scheme way to handle generic procedures that I'm not aware of ?

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  • Trim email list into domain list

    - by hanjaya
    The function below is part of a script to trim email list from a file into domain list and removes duplicates. /* define a function that can accept a list of email addresses */ function getUniqueDomains($list) { // iterate over list, split addresses and add domain part to another array $domains = array(); foreach ($list as $l) { $arr = explode("@", $l); $domains[] = trim($arr[1]); } // remove duplicates and return return array_unique($domains); } What does $domains[] = trim($arr[1]); mean? Specifically the $arr[1]. What does [1] mean in this context? How come variable $arr becomes an array variable?

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  • Java, searching within a list of objects?

    - by Rick
    I'm a bit lost on the way to make this happen the fastest. I have a large list of objects that have basic variable attributes (with getters / setters) and I need to do a search in this list to find the objects within the list that match a given parameter I have found how to do a regular list search but I need to, for example search for the value of the result of doing a call getName() for each object in the list and get objects that have a result that matches my input. Something like below where the third argument is the result of the method call and the second is what I am trying to find. int index = Collections.binarySearch(myList, "value", getName()); Any advice is appreciated

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  • How to bind a List<DateTime> to a DataGridView/ListBox .NET C#

    - by nat
    Hi there I have a List that I want to bind to a DataGridView in a windows forms app. however, I cannot for the life of me find the DataPropertyName I need to show what I want. I have had similar problems with binding this list to a listbox. what i really want is to show .ToString("dddd, dd MMMM yyyy HH:mm"), or certainly more than the standard 'date' part of the datetime - do i need to add a property of my own? public partial class DateTime{ public string myFormat{ get{return this.ToString("dddd dd MMM yyyy HH:mm");} } } or some such? thanks nat

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  • How can I traverse a reverse generic relation in a Django template?

    - by user569139
    I have the following class that I am using to bookmark items: class BookmarkedItem(models.Model): is_bookmarked = models.BooleanField(default=False) user = models.ForeignKey(User) content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey() And I am defining a reverse generic relationship as follows: class Link(models.Model): url = models.URLField() bookmarks = generic.GenericRelation(BookmarkedItem) In one of my views I generate a queryset of all links and add this to a context: links = Link.objects.all() context = { 'links': links } return render_to_response('links.html', context) The problem I am having is how to traverse the generic relationship in my template. For each link I want to be able to check the is_bookmarked attribute and change the add/remove bookmark button according to whether the user already has it bookmarked or not. Is this possible to do in the template? Or do I have to do some additional filtering in the view and pass another queryset?

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  • Flex list-controls - maintain remote data

    - by artemb
    Hello. I have a TileList which represents some remote data. I also have a form which allows me to change the data. And the data may be changed by someone else too. What is the best way to maintain data in the list in an up-to-date state? The simplest option I see is the following: Select an item in the list Edit it in the form Save it. The form submits the data to the server When the server reports success the list re-fetches it's data The very bad thing about this workflow is that the list loses selection (a tree would also loose the nodes' expanded/collapsed state). I would really love to find out another option which would enable the list to maintain it's selection state. Any guesses on how it may be done?

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  • Linked List Inserting in sorted format

    - by user2738718
    package practise; public class Node { public int data; public Node next; public Node (int data, Node next) { this.data = data; this.next = next; } public int size (Node list) { int count = 0; while(list != null){ list = list.next; count++; } return count; } public static Node insert(Node head, int value) { Node T; if (head == null || head.data <= value) { T = new Node(value,head); return T; } else { head.next = insert(head.next, value); return head; } } } This work fine for all data values less than the first or the head. anything greater than than doesn't get added to the list.please explain in simple terms thanks.

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  • python: creating a list inside a dictionary

    - by user1871081
    I just started using python and I'm trying to create a program that will read a file that looks like this: AAA x 111 AAB x 111 AAA x 112 AAC x 123 ... the file is 50 lines long and I'm trying to make the letters into keys in a dictionary and the numbers lists that correspond with the keys. I want the output to look like this: {AAA: ['111', '112'], AAB: ['111'], AAC: [123], ...} This is what I've tried file = open("filename.txt", "r") readline = file.readline().rstrip() while readline!= "": list = [] list = readline.split(" ") j = list.index("x") k = list[0:j] v = list[p + 1:] d = {} if k in d == False d[k] = [] d[k].append(v) else d[k].append(v) readline = file.readline().rstrip() I keep getting syntax errors on my if statement and I can't figure out what I've done wrong.

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  • how to solve this problem

    - by Surbir
    root@me-desktop:~# sudo apt-get install aircrack-ng Reading package lists... Done Building dependency tree Reading state information... Done The following NEW packages will be installed: aircrack-ng 0 upgraded, 1 newly installed, 0 to remove and 446 not upgraded. 1 not fully installed or removed. Need to get 1,579kB of archives. After this operation, 2,843kB of additional disk space will be used. Get:1 http://archive.ubuntu.com/ubuntu/ maverick/universe aircrack-ng i386 1:1.1-1 [1,579kB] Fetched 1,579kB in 1min 9s (22.7kB/s) Selecting previously deselected package aircrack-ng. (Reading database ... 520739 files and directories currently installed.) Unpacking aircrack-ng (from .../aircrack-ng_1%3a1.1-1_i386.deb) ... Processing triggers for man-db ... Setting up linux-image-3.0.1-030001-generic (3.0.1-030001.201108060905) ... Running depmod. update-initramfs: Generating /boot/initrd.img-3.0.1-030001-generic Warning: No support for locale: en_US.utf8 Examining /etc/kernel/postinst.d. run-parts: executing /etc/kernel/postinst.d/dkms 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic run-parts: executing /etc/kernel/postinst.d/initramfs-tools 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic run-parts: executing /etc/kernel/postinst.d/nvidia-common 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic run-parts: executing /etc/kernel/postinst.d/pm-utils 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic run-parts: executing /etc/kernel/postinst.d/update-notifier 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic run-parts: executing /etc/kernel/postinst.d/zz-update-grub 3.0.1-030001-generic /boot/vmlinuz-3.0.1-030001-generic exec: 15: update-grub: not found run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 2 Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-3.0.1-030001-generic.postinst line 1010. dpkg: error processing linux-image-3.0.1-030001-generic (--configure): subprocess installed post-installation script returned error exit status 2 Setting up aircrack-ng (1:1.1-1) ... Errors were encountered while processing: linux-image-3.0.1-030001-generic E: Sub-process /usr/bin/dpkg returned an error code (1) root@me-desktop:~#

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  • improve my code for collapsing a list of data.frames

    - by romunov
    Dear StackOverFlowers (flowers in short), I have a list of data.frames (walk.sample) that I would like to collapse into a single (giant) data.frame. While collapsing, I would like to mark (adding another column) which rows have came from which element of the list. This is what I've got so far. This is the data.frame that needs to be collapsed/stacked. > walk.sample [[1]] walker x y 1073 3 228.8756 -726.9198 1086 3 226.7393 -722.5561 1081 3 219.8005 -728.3990 1089 3 225.2239 -727.7422 1032 3 233.1753 -731.5526 [[2]] walker x y 1008 3 205.9104 -775.7488 1022 3 208.3638 -723.8616 1072 3 233.8807 -718.0974 1064 3 217.0028 -689.7917 1026 3 234.1824 -723.7423 [[3]] [1] 3 [[4]] walker x y 546 2 629.9041 831.0852 524 2 627.8698 873.3774 578 2 572.3312 838.7587 513 2 633.0598 871.7559 538 2 636.3088 836.6325 1079 3 206.3683 -729.6257 1095 3 239.9884 -748.2637 1005 3 197.2960 -780.4704 1045 3 245.1900 -694.3566 1026 3 234.1824 -723.7423 I have written a function to add a column that denote from which element the rows came followed by appending it to an existing data.frame. collapseToDataFrame <- function(x) { # collapse list to a dataframe with a twist walk.df <- data.frame() for (i in 1:length(x)) { n.rows <- nrow(x[[i]]) if (length(x[[i]])>1) { temp.df <- cbind(x[[i]], rep(i, n.rows)) names(temp.df) <- c("walker", "x", "y", "session") walk.df <- rbind(walk.df, temp.df) } else { cat("Empty list", "\n") } } return(walk.df) } > collapseToDataFrame(walk.sample) Empty list Empty list walker x y session 3 1 -604.5055 -123.18759 1 60 1 -562.0078 -61.24912 1 84 1 -594.4661 -57.20730 1 9 1 -604.2893 -110.09168 1 43 1 -632.2491 -54.52548 1 1028 3 240.3905 -724.67284 1 1040 3 232.5545 -681.61225 1 1073 3 228.8756 -726.91980 1 1091 3 209.0373 -740.96173 1 1036 3 248.7123 -694.47380 1 I'm curious whether this can be done more elegantly, with perhaps do.call() or some other more generic function?

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  • C# 4.0: Covariance And Contravariance In Generics

    - by Paulo Morgado
    C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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  • latex list environment inside the tabular environment: extra line at top preventing alignment

    - by Usagi
    Hello good people of stackoverflow. I have a LaTeX question that is bugging me. I have been trying to get a list environment to appear correctly inside the tabular environment. So far I have gotten everything to my liking except one thing: the top of the list does not align with other entries in the table, in fact it looks like it adds one line above the list... I would like to have these lists at the top. This is what I have, a custom list environment: \newenvironment{flushemize}{ \begin{list}{$\bullet$} {\setlength{\itemsep}{1pt} \setlength{\parskip}{0pt} \setlength{\parsep}{0pt} \setlength{\partopsep}{0pt} \setlength{\topsep}{0pt} \setlength{\leftmargin}{12pt}}}{\end{list}} Renamed ragged right: \newcommand{\rr}{\raggedright} and here is my table: \begin{table}[H]\caption{Tank comparisons}\label{tab:tanks} \centering \rowcolors{2}{white}{tableShade} \begin{tabular}{p{1in}p{1.5in}p{1.5in}rr} \toprule {\bf Material} & {\bf Pros} & {\bf Cons} & {\bf Size} & {\bf Cost} \\ \midrule \rr Reinforced concrete &\rr \begin{flushemize}\item Strong \item Secure \end{flushemize}&\rr \begin{flushemize}\item Prone to leaks \item Relatively expensive to install \item Heavy \end{flushemize} & 100,000 gal & \$299,400 \\ \rr Steel & \begin{flushemize}\item Strong \item Secure \end{flushemize} & \begin{flushemize}\item Relatively expensive to install \item Heavy \item Require painting to prevent rusting \end{flushemize} & 100,000 gal & \$130,100 \\ \rr Polypropylene & \begin{flushemize}\item Easy to install \item Mobile \item Inexpensive \item Prefabricated \end{flushemize} & \begin{flushemize}\item Relatively insecure \item Max size available 10,000 gal \end{flushemize} & 10,000 gal & \$5,000 \\ \rr Wood & \begin{flushemize}\item Easy to install \item Mobile \item Cheap to install \end{flushemize} & \begin{flushemize}\item Prone to rot \item Must remain full once constructed \end{flushemize} & 100,000 gal & \$86,300\\ \bottomrule \end{tabular} \end{table} Thank you for any advice :)

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  • Subset a data.frame by list and apply function on each part, by rows

    - by aL3xa
    This may seem as a typical plyr problem, but I have something different in mind. Here's the function that I want to optimize (skip the for loop). # dummy data set.seed(1985) lst <- list(a=1:10, b=11:15, c=16:20) m <- matrix(round(runif(200, 1, 7)), 10) m <- as.data.frame(m) dfsub <- function(dt, lst, fun) { # check whether dt is `data.frame` stopifnot (is.data.frame(dt)) # check if vectors in lst are "whole" / integer # vector elements should be column indexes is.wholenumber <- function(x, tol = .Machine$double.eps^0.5) abs(x - round(x)) < tol # fall if any non-integers in list idx <- rapply(lst, is.wholenumber) stopifnot(idx) # check for list length stopifnot(ncol(dt) == length(idx)) # subset the data subs <- list() for (i in 1:length(lst)) { # apply function on each part, by row subs[[i]] <- apply(dt[ , lst[[i]]], 1, fun) } # preserve names names(subs) <- names(lst) # convert to data.frame subs <- as.data.frame(subs) # guess what =) return(subs) } And now a short demonstration... actually, I'm about to explain what I primarily intended to do. I wanted to subset a data.frame by vectors gathered in list object. Since this is a part of code from a function that accompanies data manipulation in psychological research, you can consider m as a results from personality questionnaire (10 subjects, 20 vars). Vectors in list hold column indexes that define questionnaire subscales (e.g. personality traits). Each subscale is defined by several items (columns in data.frame). If we presuppose that the score on each subscale is nothing more than sum (or some other function) of row values (results on that part of questionnaire for each subject), you could run: > dfsub(m, lst, sum) a b c 1 46 20 24 2 41 24 21 3 41 13 12 4 37 14 18 5 57 18 25 6 27 18 18 7 28 17 20 8 31 18 23 9 38 14 15 10 41 14 22 I took a glance at this function and I must admit that this little loop isn't spoiling the code at all... BUT, if there's an easier/efficient way of doing this, please, let me know!

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  • Linked list recursive reverse

    - by Phoenix
    I was looking at the code below from stanford library: void recursiveReverse(struct node** head_ref) { struct node* first; struct node* rest; /* empty list */ if (*head_ref == NULL) return; /* suppose first = {1, 2, 3}, rest = {2, 3} */ first = *head_ref; rest = first->next; /* List has only one node */ if (rest == NULL) return; /* put the first element on the end of the list */ recursiveReverse(&rest); first->next->next = first; /* tricky step -- see the diagram */ first->next = NULL; /* fix the head pointer */ *head_ref = rest; } What I don't understand is in the last recursive step for e.g if list is 1-2-3-4 Now for the last recursive step first will be 1 and rest will be 2. So if you set *head_ref = rest .. that makes the head of the list 2 ?? Can someone please explain how after reversing the head of the list becomes 4 ??

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  • std::list iterator: get next element

    - by sheepsimulator
    I'm trying to build a string using data elements stored in a std::list, where I want commas placed only between the elements (ie, if elements are {A,B,C,D} in list, result string should be "A,B,C,D". This code does not work: typedef std::list< shared_ptr<EventDataItem> > DataItemList; // ... std::string Compose(DataItemList& dilList) { std::stringstream ssDataSegment; for(iterItems = dilList.begin(); iterItems != dilList.end(); iterItems++) { // Lookahead in list to see if next element is end if((iterItems + 1) == dilList.end()) { ssDataSegment << (*iterItems)->ToString(); } else { ssDataSegment << (*iterItems)->ToString() << ","; } } return ssDataSegment.str(); } How do I get at "the-next-item" in a std::list using an iterator? I would expect that it's a linked-list, why can't I get at the next item?

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  • std::list : get next element

    - by sheepsimulator
    I'm trying to build a string using data elements stored in a std::list, where I want commas placed only between the elements (ie, if elements are {A,B,C,D} in list, result string should be "A,B,C,D". This code does not work: typedef std::list< shared_ptr<EventDataItem> > DataItemList; // ... std::string Compose(DataItemList& dilList) { std::stringstream ssDataSegment; for(iterItems = dilList.begin(); iterItems = dilList.end(); iterItems++) { // Lookahead in list to see if next element is end if((iterItems + 1) == dilList.end()) { ssDataSegment << (*iterItems)->ToString(); } else { ssDataSegment << (*iterItems)->ToString() << ","; } } return ssDataSegment.str(); } How do I get at "the-next-item" in a std::list using an iterator? I would expect that it's a linked-list, why can't I get at the next item?

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  • C# Changing Objects within a List

    - by kwong22
    Hi, I'm having a little problem changing members of an object in a list using a found index. So this is the method I am currently working with: static void addToInventory(ref List<baseItem> myArray, baseItem item, float maxAmount, ref float currentAmount) { if (currentAmount + item.getWeight() <= maxAmount) { Console.WriteLine("item.Quantity = {0}", item.Quantity); if (myArray.Contains(item)) { Console.WriteLine("Item ({0}) already exists", item.Name); int id = myArray.IndexOf(item); myArray[id].Quantity += item.Quantity;//Change occurs in this line, item.Quantity becomes the same as myArray[id].Quantity } else { Console.WriteLine("Adding new item ({0})", item.Name); myArray.Add(item); } currentAmount += item.getWeight(); } else { Console.WriteLine("Inventory full"); } myArray.Sort(); } This method takes several parameters including the inventory/list. I check if the item fits in and if it does, I see if there is another item of the same name in the list, find the index, and add more of the item. However, the quantity of the item added suddenly becomes the same as the quantity of the item in the list. For some reason, this also changes the quantity of the item outside of the list. So therefore, instead of quantities adding up like this: 1, 2, 3, 4, they add up like this: 1, 2, 4, 8. I've just started to learn how to use lists so if there is anything I'm missing, don't hesitate to criticize. Thanks in advance.

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  • List modification in Python

    - by user2945143
    We are given an algorithm to modify a list of numbers from 1 to 28. There are 5 steps in the algorithm. We have written functions for each step (all correct). We need to write a function that combines all 5 steps. The algorithm modifies the list to get a value. Each time you get a new value, you use the list created by the algorithm from the previous step. This is what we have gotten so far for the code: get_card_at_top_index(insert_top_to_bottom(triple_cut((move_joker_2( move_joker_1(deck)))))) When we run the code to generate the get_card_at_top_index, the first answer is correct. However, the rest are not. Instead of using from the new list, python uses the value that it generated from the last step. What did we do wrong? UPDATE: The other 5 codes passed the tests, they are correct. Code 1 (List) = list1 Code 2 (list1) = list2 Code 3 (list2) = list3 Code 4 (list3) = list4 Code 5 (list4) = list5 we generate a number from 5. We need to run the algorithm again to generate 25 more numbers. We will use list 5 start from step 1

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  • F# insert/remove item from list

    - by Timothy
    How should I go about removing a given element from a list? As an example, say I have list ['A'; 'B'; 'C'; 'D'; 'E'] and want to remove the element at index 2 to produce the list ['A'; 'B'; 'D'; 'E']? I've already written the following code which accomplishes the task, but it seems rather inefficient to traverse the start of the list when I already know the index. let remove lst i = let rec remove lst lst' = match lst with | [] -> lst' | h::t -> if List.length lst = i then lst' @ t else remove t (lst' @ [h]) remove lst [] let myList = ['A'; 'B'; 'C'; 'D'; 'E'] let newList = remove myList 2 Alternatively, how should I insert an element at a given position? My code is similar to the above approach and most likely inefficient as well. let insert lst i x = let rec insert lst lst' = match lst with | [] -> lst' | h::t -> if List.length lst = i then lst' @ [x] @ lst else insert t (lst' @ [h]) insert lst [] let myList = ['A'; 'B'; 'D'; 'E'] let newList = insert myList 2 'C'

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  • Example of DOD design (on a generic Zombie game)

    - by Jeffrey
    I can't seem to find a nice explanation of the Data Oriented Design for a generic zombie game (it's just an example, pretty common example). Could you make an example of the Data Oriented Design on creating a generic zombie class? Is the following good? Zombie list class: class ZombieList { GLuint vbo; // generic zombie vertex model std::vector<color>; // object default color std::vector<texture>; // objects textures std::vector<vector3D>; // objects positions public: unsigned int create(); // return object id void move(unsigned int objId, vector3D offset); void rotate(unsigned int objId, float angle); void setColor(unsigned int objId, color c); void setPosition(unsigned int objId, color c); void setTexture(unsigned int, unsigned int); ... void update(Player*); // move towards player, attack if near } Example: Player p; Zombielist zl; unsigned int first = zl.create(); zl.setPosition(first, vector3D(50, 50)); zl.setTexture(first, texture("zombie1.png")); ... while (running) { // main loop ... zl.update(&p); zl.draw(); // draw every zombie } Or would creating a generic World container that contains every action from bite(zombieId, playerId) to moveTo(playerId, vector) to createPlayer() to shoot(playerId, vector) to face(radians)/face(vector); and contains: std::vector<zombie> std::vector<player> ... std::vector<mapchunk> ... std::vector<vbobufferid> player_run_animation; ... be a good example? Whats the proper way to organize a game with DOD?

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  • Ideal data structure/techniques for storing generic scheduler data in C#

    - by GraemeMiller
    I am trying to implement a generic scheduler object in C# 4 which will output a table in HTML. Basic aim is to show some object along with various attributes, and whether it was doing something in a given time period. The scheduler will output a table displaying the headers: Detail Field 1 ....N| Date1.........N I want to initialise the table with a start date and an end date to create the date range (ideally could also do other time periods e.g. hours but that isn't vital). I then want to provide a generic object which will have associated events. Where an object has events within the period I want a table cell to be marked E.g. Name Height Weight 1/1/2011 2/1/2011 3/1/20011...... 31/1/2011 Ben 5.11 75 X X X Bill 5.7 83 X X So I created scheduler with Start Date=1/1/2011 and end date 31/1/2011 I'd like to give it my person object (already sorted) and tell it which fields I want displayed (Name, Height, Weight) Each person has events which have a start date and end date. Some events will start and end outwith but they should still be shown on the relevant date etc. Ideally I'd like to have been able to provide it with say a class booking object as well. So I'm trying to keep it generic. I have seen Javasript implementations etc of similar. What would a good data structure be for this? Any thoughts on techniques I could use to make it generic. I am not great with generics so any tips appreciated.

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  • 3.2.0-31-generic version doesn't boot

    - by user92526
    12.04 used to work just fine a month ago. Since August, I installed all of the available updates. Since then my mac-pro is acting weird. If I restart the computer, the screen gets stuck in the purple back ground without any texts. Then if I restart again, I can choose what versions of linux I want to run. If I select 3.2.0-31-generic, the machine gets stuck in a state of blinking cursor. If I boot again to run 3.2.0-31-generic recovery mode, the machine gets stuck in a "..... memory freed End of Stack" mode. I can't boot through this kernel. I have to choose an older version of linux like 3.2.0-12-generic to boot into my mac pro, but I have too boot twice to get into this version. I was wondering --if you could provide me a solution to boot the 3.2.0-31-generic version. -- if you could provide me a solution to boot into any version the first time I restart. (Usually I have to kill the first restart) --- If there is an option in linux to choose what version I want to run every time I restart so that I don't have to choose everytime. Thank you

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  • Convert List of one type to Array of another type using Dozer

    - by aheu
    I'm wondering how to convert a List of one type to an array of another type in Java using Dozer. The two types have all the same property names/types. For example, consider these two classes. public class A{ private String test = null; public String getTest(){ return this.test } public void setTest(String test){ this.test = test; } } public class B{ private String test = null; public String getTest(){ return this.test } public void setTest(String test){ this.test = test; } } I've tried this with no luck. List<A> listOfA = getListofAObjects(); Mapper mapper = DozerBeanMapperSingletonWrapper.getInstance(); B[] bs = mapper.map(listOfA, B[].class); I've also tried using the CollectionUtils class. CollectionUtils.convertListToArray(listOfA, B.class) Neither are working for me, can anyone tell me what I am doing wrong? The mapper.map function works fine if I create two wrapper classes, one containing a List and the other a b[]. See below: public class C{ private List<A> items = null; public List<A> getItems(){ return this.items; } public void setItems(List<A> items){ this.items = items; } } public class D{ private B[] items = null; public B[] getItems(){ return this.items; } public void setItems(B[] items){ this.items = items; } } This works oddly enough... List<A> listOfA = getListofAObjects(); C c = new C(); c.setItems(listOfA); Mapper mapper = DozerBeanMapperSingletonWrapper.getInstance(); D d = mapper.map(listOfA, D.class); B[] bs = d.getItems(); How do I do what I want to do without using the wrapper classes (C & D)? There has got to be an easier way... Thanks!

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