Why is the first element in an array always 0? -

-

I am thinking that where the idea of ​​the first element in an array came from zero. Why is not this 1? I have used for the fact that it is zero, but the first element can not be due to being zero.

An array is a block of sequential memory if the array starts with memory address x , Then the first element is in the address x + 0 , the second is on the x + sizeof (arraytype) , the third x + 2 * sizeof (Arraytype) is on , etc.


Comments

Post a Comment

Popular posts from this blog

c# - SignalR: "Protocol error: Unknown transport." when navigating to hub -

-
Image
I am trying to use the ASP.NET signal for the first time - here's what I did: created a new web Has been added to the project and the following signal R packages: I have created the following category: [Hub-name ("chat")] Public class ChatHub: Hub {Public Zero Halo () {Clients.All.hello ( ); }} and the following startup configuration: public partial class startup {public zero configuration (IAppBuilder app) {configure (app); App.MapSignalR (); }} However, whenever I navigate localhost: (port) / api / signalr / chat I get the following error: Protocol error: Unknown transport. I am running a new browser and trying different people so remove it from the API / URL, and just use the localhost: (potter) / signaller / Chat
Read more

class - Kivy: how to instantiate a dynamic classes in python -

-
Using KV lang on my Python code, I have taken a hard time trying to instantiate a dynamic class, the following Consider the code: My test.kv file looks like this: & lt; MyPopup @ popup: Title: 'Hello' size_hunt: (1, .6) Grid layout: ID: RouteGrid column: 2 padding: ['8dp', '4dp', '8dp', '4dp'] Difference: '8dp' label: text: 'some text here' button: text: 'OK' On_press: do_something () & lt; MyGrid & gt;: Rows: 1 Button: Text: 'Show Popup' on_press: root.pop.show () Then import Kivy.app into my test.py: I get the following error: raise Factory Exception ('Uncount Class' '% name) kivy.factory.FactoryException: Unknown class Can anyone tell me how to do this properly, what do I remember? If you need more information please let me know Thank you. Takes a call to the factory before the KV file is loaded, so you want the class to Are not yet in existence. As long as no clas...
Read more

python - mayavi mapping a discrete colorbar on a surface -

-
Image
I want to change the color of the surface on the basis of another value (an ID) that is considered discrete (hence I In the simplified example given below, I have prepared a field with 3 different IDs: 0 / red on left 2 / blue 1 / green left But with the code below, I have some strange behavior on the border between red and blue (green Point) I think this is probably due to an interpolation! Code: import from import mlab np # np # my dataset -simplified-x, y, z = np.mgrid [-3: 3: 100] H, -3: 3: 100h, -3: 3: 100 h] value = NP. SQLT (x ** 2 + y ** 2 + z ** 2) # My color value: Volume is divided into 3 sub-versions taking colorvalues ​​with X = np.empty (values.shape) colorvalues [0:33,:,:] = 0 colorvalues ​​[33:66,:,:] = 2. Look [66:,:,:] = 1 src = mlab.pipeline.scalar_field (value) src.image_data.point_data.add_array (colorvalues.T.ravel ()) (1) .name = 'MyID' src.image_data. point_data.update src.image_data.point_data.get_array () # surface, contour = mlab.pipe...
Read more