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Currently when I use "python" command, it points to python2.6. I have installed python3.1 and I want the "python" command point to python3.1. How it is possible? mahmood@mpc:~$ which python /usr/bin/python mahmood@mpc:~$ ls -l /usr/bin/python lrwxrwxrwx 1 root root 9 2010-11-24 16:14 /usr/bin/python -> python2.6 mahmood@mpc:~$ uname -a Linux orca 2.6.32-24-server #39-Ubuntu SMP Wed Jul 28 06:21:40 UTC 2010 x86_64 GNU/Linux Since you have Linux, and if you want to simply type "python" instead of "python3" in order to run Python programs, a solution is simply to define an alias in you shell

Currently I have JSON that either comes in via an HTTP call or is stored in a database but during server processing they are mapped to C# objects. These objects have properties like public List<int> MyArray . When the JSON contains MyArray:null I want the resulting property to be an empty List<T> instead of a null List<T> property. The goal is that the object will "reserialize" to JSON as MyArray:[] , thus either saving to the database or responding out via HTTP as an empty array instead of null . That way, no matter what, the C# class is basically scrubbing and enforcing an empty array for

Say I have a struct that looks like this (a POD): struct Foo { int i; double d; }; What are the differences between the following two lines: Foo* f1 = new Foo; Foo* f2 = new Foo(); The first one leaves the values uninitialised; the second initialises them to zero. This is only the case for POD types, which have no constructors. I suppose nothing at all. Foo() is allowed, even if it makes no sense... I've tried to change struct into class and tried a diff on the generated exe, and they resulted to be the same, meaning that a class without method is like a struct from a practical and "effective"

How can I make default value for a field to be taken from existing objects of a model? I tried these and it didn't worked: 1) class ModelA(models.Model): fieldA = models.CharField(default=self.get_previous()) def get_previous(self): return ModelA.objects.all()[0].fieldA NameError: name 'self' is not defined 2) class ModelA(models.Model): fieldA = models.CharField(default=ModelA.get_previous()) @staticmethod def get_previous(): return ModelA.objects.all()[0].fieldA NameError: name 'ModelA' is not defined 3) class ModelA(models.Model): fieldA = models.CharField(default=get_previous()) def get

Can anybody tell me what is the default value of a variable at the time of declaration in C# and vb?? In c# you can use the default keyword to determine default values. For example: default(bool) default(int) default(int?) Do you mean a (method) variable? or a field (on an instance or type)? For a method-level variable (in C# at least) it is irrelevant, since "definite assignment" means that you must give it a value before you can read it. Fields default to the bitwise zero state: for reference types (including string) that means null for Nullable<T> ( int? etc) that means null for numerics

How I can do custom Java annotation with no attribute name inside parentheses? I don't want this: @annotation_name(att=valor) . I just want like in Servlets, i.e: @WebServlet("/main") Define the annotation with an attribute named value , then the attribute name can be omitted: @interface CustomAnnotation { String value(); } This can be used like so: @CustomAnnotation("/main") // ... You specify an attribute named value: public @interface MyAnnotation { String value(); } This doesn't have to be the only attribute if they have default values: public @interface MyAnnotation { String value(); int

I am using PyCharm 3.4.1 on Ubuntu 14.04. For new project it suggests ~/PyCharmProjects for storing project folders. Is it possible to change the location and name of this proposed folder? (I couldn't find any reference to changing it in the interface, on the JetBrains site, or in the settings files. Either it isn't possible or (I hope) I missed something.) Note, it is not a duplicate of Can I change the location/name of PyCharmProjects? - I am aware that it is possible to change proposed path for every created project - but I want defaults that I like. In fact, this is possible. In the IDE