list

问题 I'm writing a program to read text from a file into a list, split it into a list of words using the split function. And for each word, I need to check it if its already in the list, if not I need to add it to the list using the append function. The desired output is: ['Arise', 'But', 'It', 'Juliet', 'Who', 'already', 'and', 'breaks', 'east', 'envious', 'fair', 'grief', 'is', 'kill', 'light', 'moon', 'pale', 'sick', 'soft', 'sun', 'the', 'through', 'what', 'window', 'with', 'yonder'] My output

问题 I have a backgroundWorker that is processing two lists. I need to pass the Lists to the worker. the result is empty lists. Code to pass the Lists (and 2 other parameters). In my test, each list has 20+ items, and the List<> items show that the 20+ items are intact just prior to the call. In the inspector they say "Count" followed by the number of items. List<Object> arguments = new List<object>(); // Add arguments to pass to background worker arguments.Add(managerSource); arguments.Add

问题 In my application I am receiving a string 'abc[0]=123' I want to convert this string to an array of items. I have tried eval() it didnt work for me. I know the array name abc but the number of items will be different in each time. I can split the string, get array index and do. But I would like to know if there is any direct way to convert this string as an array insert. I would greately appreciate any suggestion. 回答1: are you looking for something like In [36]: s = "abc[0]=123" In [37]: vars

问题 suppose I have a list that comes from a database like this: List<Item> list = { new Item { TypeID = 2, Count = 5 }, new Item { TypeID = 2, Count = 7 }, new Item { TypeID = 5, Count = 2 } }; I would like to sum up all elements with the same TypeID so that I have a final result list with two elements only: List<Item> list = { new Item { TypeID = 2, Count = 12 }, new Item { TypeID = 5, Count = 2 } }; How can I achive this using LINQ? Cheers Simon 回答1: You can use GroupBy to group by TypeID first

问题 If I have a list: list_1 = ["apples", "apricots", "oranges"] and I append an new item to the list : "berries" list_1 = ["apples", "apricots", "oranges", "berries"] Under-the-hood (so to speak), I thought I remember reading that Python creates another list (list_2) and points it to the original list (list_1) so that list_1 remains static...if this is true, would it look something like this (under-the-hood)? list_1 = ["apples", "apricots", ["oranges", "berries"]] So in this way, the original

问题 I'm trying to evaluate an expression using a binary tree. The tree has this characteristics: Each node has zero, one or two children. Only nodes containing operators can have children. All leaf nodes must be numbers. For the sake of simplicity, the only operators allowed are * and + Something like those ones: This is my tree class: class ExpressionTree { struct Node { std::string data; Node *leftChild, *rightChild; Node(std::string d): data(d), leftChild(NULL), rightChild(NULL) {} } *root;

问题 I have two lists and a class public class CommonLog { public string Break { get; set; } public string Cart { get; set; } public string Length { get; set; } } This is list one commonlog.Add(new CommonLog { Break = breakTimeVar, Cart = cartVar, Length = lengthHours }); and one like this list 2 commonlog2.Add(new CommonLog { Break = breakTimeVar2, Cart = cartVar2, Length = lengthHours2 }); The two pieces of information I need to match are as follows List 1 contains this 0016 009130 00:01:30 List

问题 I'm new here and to programming as well. I don't know if I put the question right, but I have been trying to generate sublists from a list. i.e say if L = range(5) , generate sublists from L as such [[],[0],[0,1],[0,1,2],[0,1,2,3],[0,1,2,3,4]] . Kindly assist. Thanks. 回答1: Look at this: >>> # Note this is for Python 2.x. >>> def func(lst): ... return map(range, xrange(len(lst)+1)) ... >>> L = range(5) >>> func(L) [[], [0], [0, 1], [0, 1, 2], [0, 1, 2, 3], [0, 1, 2, 3, 4]] >>> 回答2: You can

问题 Could you please help me? I want to make a list based on information contained in an R data frame. I found a solution, but it is not general. For instance, let's start with this data frame: df <- data.frame(vertices = paste(letters[1:20]), modules = rep(1:4, 5)) I want to use df$modules to turn the data frame into a list. The items of the list should contain data from df$vertices . So I found this solution: list1 <- split(df, df$modules) list2 <- vector(mode = "list", length = length(unique

问题 Could you please help me? I want to make a list based on information contained in an R data frame. I found a solution, but it is not general. For instance, let's start with this data frame: df <- data.frame(vertices = paste(letters[1:20]), modules = rep(1:4, 5)) I want to use df$modules to turn the data frame into a list. The items of the list should contain data from df$vertices . So I found this solution: list1 <- split(df, df$modules) list2 <- vector(mode = "list", length = length(unique