collections

问题 Here's the fiddle: http://jsfiddle.net/QhQ8D/10/ Code is down below. Making a chat app and need a sorted, connected user list. Figured Collection with a comparator on name hooked to a CompositeView should do it. Am I doing something wrong in the implementation here? HTML: <div>Enter user name and hit add user to build your list</div> <div id="divadduser"> <input id="inputusername"/> <input id="buttonadduser" type="button" value="add user"/> </div> <div id="divusers"></div> JAVASCRIPT: var

问题 I have this df: import pandas as pd a = [1,1,1,2,2,3,3,3,3,4,4,5,5,5] b = ["pi","pi","k","J","pi","pi","k","k","J","pi","k","pi","k","pi"] bin0 = [0,0,0,1,0,0,1,0,0,0,1,1,0,0] bin1 = [1,1,1,0,1,0,0,1,1,0,0,0,1,0] bin2 = [0,0,0,0,0,1,0,0,0,1,0,0,0,1] df_test = pd.DataFrame({"a": a, "b": b,"bin0": bin0,"bin1": bin1,"bin2": bin2}) Like this: a b bin0 bin1 bin2 0 1 pi 0 1 0 1 1 pi 0 1 0 2 1 k 0 1 0 3 2 J 1 0 0 ... 12 5 k 0 1 0 13 5 pi 0 0 1 Then I want to create dictionaries from this df and sum

问题 The Blackberry JDE does not include java.util.ArrayList , even though it knows about java.util ? What's up with that? Is there an equivalent class for BB? I don't want to use an array, really, because I have an unknown number of objects I'm dealing with. why does the Blackberry JDE leave so much out? 回答1: Well they are Java from a language standpoint. It just doesn't support all of the standard edition packages. It falls more inline with the microedition standards, but is way beyond J2ME from

问题 I understand that when an object is added to a List, the List retains a reference to that object based on answer from this question Is this java Object eligible for garbage collection in List How then how do you make the object in the List eligible for garbage collection so that it's removed from the heap and not taking up memory? I ask because in JavaFX, a Vboxs getChildren method returns observable list containing the children nodes of the vbox. If a UI element is removed but not eligible

问题 I have an ArrayList of Objects(POJOs) that have an Id and another field. I have implemented the equals()/hashcode() override in the POJO for the Id field. When I compare two objects using the equals() method of the Object class, it works perfectly fine. However when I add these objects to an arraylist and implement the Collections.sort(arrListOfObjects); it gives me a classCastexception. I looked up and found that I need to implement a Comparator. This comparator also does something to equals

问题 I have written a piece of code where I'm checking the size of an ArrayList like: [1,2,3].size All works well on Groovy Console and with Grails embedded Tomcat server. But once I deployed this code to Websphere Application Server, I receivec an exception stating Exception evaluating property 'size' for java.util.ArrayList, Reason: groovy.lang.MissingPropertyException: No such property: size for class: java.lang.Integer. After a while of debugging, testing and plenty of WTFs, I realized that

问题 I have written a piece of code where I'm checking the size of an ArrayList like: [1,2,3].size All works well on Groovy Console and with Grails embedded Tomcat server. But once I deployed this code to Websphere Application Server, I receivec an exception stating Exception evaluating property 'size' for java.util.ArrayList, Reason: groovy.lang.MissingPropertyException: No such property: size for class: java.lang.Integer. After a while of debugging, testing and plenty of WTFs, I realized that

问题 My domain classes have collections that look like this: private List<Foo> _foos = new List<Foo>(); public virtual ReadOnlyCollection<Foo> Foos { get { return _foos.AsReadOnly(); } } This gives me readonly collections that can be modified from within the class (i.e. by using the field _foos). This collection is mapped as follows (Fluent NHibernate): HasMany(x => x.Foos).KeyColumn("ParentClassId").Cascade.All().Inverse().Access.CamelCaseField(Prefix.Underscore); Now when I try to use this

问题 This question already has answers here : Collection was modified; enumeration operation may not execute in ArrayList [duplicate] (9 answers) Closed 6 years ago . This question is asked many a time in this forum. I know solution for the problem. But I am curious to know why "Enumeration operation can not execute when a collection is modified" List<string> list = new List<string>(); list.Add("a"); list.Add("b"); int[] array = new int[6] { 1, 2, 3, 4, 5, 5 }; HashSet<int> hashSet = new HashSet

问题 This question already has answers here : Collection was modified; enumeration operation may not execute in ArrayList [duplicate] (9 answers) Closed 6 years ago . This question is asked many a time in this forum. I know solution for the problem. But I am curious to know why "Enumeration operation can not execute when a collection is modified" List<string> list = new List<string>(); list.Add("a"); list.Add("b"); int[] array = new int[6] { 1, 2, 3, 4, 5, 5 }; HashSet<int> hashSet = new HashSet