If we have a list, and each item can have different length. For example: l <- list(c(1, 2), c(3, 4,5), c(5), c(6,7)) (In order to be clear, we will call objects in a list “items”, and objects in the objects of list “elements”.) How can we extract, for example the first element of each item? … Read more
I cannot find out can to get a list of all entry of the sublists? Here’s a simple example, a list o lists: listoflists <- list(“A”=list(c(1,2,3),c(2,34,2)), “B” = list(c(1,2),c(2,3,2,1)), “C” = list(c(“sdf”,3,2))) $A $A[[1]] [1] 1 2 3 $A[[2]] [1] 2 34 2 $B $B[[1]] [1] 1 2 $B[[2]] [1] 2 3 2 1 $C … Read more
Many people and authors suggested to us to use list than array. List <Integer> list = new ArrayList<Integer>(); list.addElement(1); …. What it is the reason behind it? Answer You should generally prefer to choose the right data structure for the job. You need to understand your task at hand as well as all the different … Read more
how can I get a list of alle domain classes I use in my project? Something like GORM.domains.list(). Answer Using grailsApplication.getArtefacts(“Domain”) you get a list of GrailsDomainClass instances that hold meta-information regarding the domain class. The domain class itself is returned by Calling getClazz(). In short: grailsApplication.getArtefacts(“Domain”)*.clazz returns a complete list of the existing domain … Read more
I am a beginner at Python, and to those who holds negative thoughts against my post, please leave. I am simply seeking help here and trying to learn. I’m trying to check within a simple data set the 0s and 1s. This will be used towards defining voids and solids on floor plans to define … Read more
I’m trying to find a value in a list of objects in kotlin, using for it “filter”, but I need to return true or false if the value is found, but filter returns me a list of object in the case of match. t.filter { it.retailerId == value } ¿How I can return a boolean … Read more
I want to use a class instance as a dictionary key, like: classinstance = class() dictionary[classinstance] = ‘hello world’ Python seems to be not able to handle classes as dictionary key, or am I wrong? In addition, I could use a Tuple-list like [(classinstance, helloworld),…] instead of a dictionary, but that looks very unprofessional. Do … Read more
I am having a List<Tuple<string,string>> tr = new List<Tuple<string,string>>(); tr.Add(new Tuple<string, string>(“Test”,”Add”); tr.Add(new Tuple<string, string>(“Welcome”,”Update”); foreach (var lst in tr) { if(lst.Contains(“Test”)) MessageBox.Show(“Value Avail”); } I failed while doing this ,…. Answer If you’d like to use LINQ: if(tr.Any(t => t.Item1 == “Test” || t.Item2 == “Test”)) MessageBox.Show(“Value Avail”); This will also have the benefit … Read more
How do I merge 2 lists in such a way that the resulting list contains the elements of 2 lists in alternating fashion in Scala. Input: val list1 = List(“Mary”, “a”, “lamb”) val list2 = List(“had”, “little”) Output: List(“Mary”, “had”, “a”, “little”, “lamb”) Answer What you’re looking for is usually called “intersperse” or “intercalate” and … Read more
I am trying to improve the memory usage of my script in python, therefore I need to know what’s RAM usage of my list. I measure the memory usage with print str(sys.getsizeof(my_list)/1024/1024) which hopefully would give me the size of the list in RAM in Mb. it outputs 12 Mb, however in top command I … Read more
