call

I know that __call__ method in a class is triggered when the instance of a class is called. However, I have no idea when I can use this special method, because one can simply create a new method and perform the same operation done in __call__ method and instead of calling the instance, you can call the method. I would really appreciate it if someone gives me a practical usage of this special method. Django forms module uses __call__ method nicely to implement a consistent API for form validation. You can write your own validator for a form in Django as a function. def custom_validator(value):

This question already has an answer here: subprocess.call using string vs using list 1 answer I am trying to get python's subprocess.call method to accept some args commands through a list (consisting of a sequence of strings) as advised in the python documentation. To explore this behavior before putting it into my actual script, I opened up IPython, ran some commands involving different combinations of shell settings and args commands and got the following behavior: In [3]: subprocess.call(['ls', '-%sl' %'a']) total 320 drwxr-xr-x 20 Kohaugustine staff 680 Oct 15 16:55 . drwxr-xr-x 5

I try to sort my thoughts about how javascript's bind() works. I see that if I do var f = function (a) { ... } var g = f.bind(obj); g(1) then f is called with obj as this and 1 as a . What I thought is g is a wrapper function around f. But when I do var f = function (a) { ... } var g = f.bind(obj); g.call(1) then f is called with 1 as this and a undefined. So it seems g is not just a simple wrapper, but call somehow differentiates between normal and bound functions. One more thing is I cannot partially apply a function more times. var f = function (a) { ... } var g = f.bind(obj); var h = g

I'm a beginner and I've always read that it's bad to repeat code. However, it seems that in order to not do so, you would have to have extra method calls usually. Let's say I have the following class public class BinarySearchTree<E extends Comparable<E>>{ private BinaryTree<E> root; private final BinaryTree<E> EMPTY = new BinaryTree<E>(); private int count; private Comparator<E> ordering; public BinarySearchTree(Comparator<E> order){ ordering = order; clear(); } public void clear(){ root = EMPTY; count = 0; } } Would it be more optimal for me to just copy and paste the two lines in my clear()

Now I have two classes allmethods.cs and caller.cs . I have some methods in class allmethods.cs . I want to write code in caller.cs in order to call a certain method in the allmethods class. Example on code: public class allmethods public static void Method1() { // Method1 } public static void Method2() { // Method2 } class caller { public static void Main(string[] args) { // I want to write a code here to call Method2 for example from allmethods Class } } How can I achieve that? Because the Method2 is static, all you have to do is call like this: public class AllMethods { public static void

I'm new to C# and i really need to know how to call/use a string from another method. For example: public void button1_Click(object sender, EventArgs e) { string a = "help"; } public void button2_Click(object sender, EventArgs e) { //this is where I need to call the string "a" value from button1_click string b = "I need "; string c = b + a; } So in this example I need to call string " a " defined in function button1_Click() from function button2_Click() Thanks!! Usually you'd pass it as an argument, like so: void Method1() { var myString = "help"; Method2(myString); } void Method2(string

I have the following code. I cannot for the life of me figure it out. I want to call a different sub depending on the value of i . For example, if i = 1 it should call sale_call1 and if i = 2 it should call sale_call2 . Private Sub test_Click() Dim i As String Dim pro As String i = Me.tb1.Value pro = "sale_call" + i If i = "1" Then Call pro Else Call pro End If End Sub Sub sale_call1() MsgBox "Hello" End Sub Sub sale_call2() MsgBox "goodbye" End Sub Try this Replace Call pro with Application.Run pro Example Private Sub test_Click() Dim i As String Dim pro As String i = 1 pro = "sale_call" + i

I use the Call keyword when calling subs in VB/VBA. I know it's optional, but is it better to use it or leave it off? I've always thought it was more explicit, but maybe it's just noise. Also, I read this on another forum: Using the Call keyword is faster because it knows that it is not going to return any values, so it doesn't need to set up any stackspace to make room for the return value. Ah ha. I have long wondered about this and even reading a two inch thick book on VBA basically says don't use it unless you want to use the Find feature of the VBE to easily find calls in large projects.