Tutorial by Examples

views.py: from django.http import HttpResponse from django.views.generic import View class MyView(View): def get(self, request): # <view logic> return HttpResponse('result') urls.py: from django.conf.urls import url from myapp.views import MyView urlpatterns...

Adding properties If you'd like to add properties to an existing object, you can use the Add-Member cmdlet. With PSObjects, values are kept in a type of "Note Properties" $object = New-Object -TypeName PSObject -Property @{ Name = $env:username ID = 12 Address...

You may need to expand or shrink your pointer storage space after you have allocated memory to it. The void *realloc(void *ptr, size_t size) function deallocates the old object pointed to by ptr and returns a pointer to an object that has the size specified by size. ptr is the pointer to a memory b...

Since C++14, the standard provides the class template template <class T, T... Ints> class integer_sequence; template <std::size_t... Ints> using index_sequence = std::integer_sequence<std::size_t, Ints...>; and a generating metafunction for it: template <class T, T N&g...

A simple way of selecting between functions at compile time is to dispatch a function to an overloaded pair of functions that take a tag as one (usually the last) argument. For example, to implement std::advance(), we can dispatch on the iterator category: namespace details { template <clas...

The array_intersect function will return an array of values that exist in all arrays that were passed to this function. $array_one = ['one', 'two', 'three']; $array_two = ['two', 'three', 'four']; $array_three = ['two', 'three']; $intersect = array_intersect($array_one, $array_two, $array_thre...

git difftool -t meld --dir-diff will show the working directory changes. Alternatively, git difftool -t meld --dir-diff [COMMIT_A] [COMMIT_B] will show the differences between 2 specific commits.

Using the Android API 23 or higher, very often such situation can be seen: This situation is caused by the structural change of the Android API regarding getting the resources. Now the function: public int getColor(@ColorRes int id, @Nullable Theme theme) throws NotFoundException should...

Define a menu in res/menu <?xml version="1.0" encoding="utf-8"?> <menu xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"> <item android:id="@+id/first_...

git diff myfile.txt Shows the changes between the previous commit of the specified file (myfile.txt) and the locally-modified version that has not yet been staged. This also works for directories: git diff documentation The above shows the changes between the previous commit of all files in ...

Suppose you have a Dockerfile ending with ENTRYPOINT [ "nethogs"] CMD ["wlan0"] if you build this image with a docker built -t inspector . launch the image built with such a Dockerfile with a command such as docker run -it --net=host --rm inspector ,nethogs will monitor the...

If someone else wrote the code you are committing, you can give them credit with the --author option: git commit -m "msg" --author "John Smith <[email protected]>" You can also provide a pattern, which Git will use to search for previous authors: git commit -m &quo...

Python makes it very simple to check whether an item is in a list. Simply use the in operator. lst = ['test', 'twest', 'tweast', 'treast'] 'test' in lst # Out: True 'toast' in lst # Out: False Note: the in operator on sets is asymptotically faster than on lists. If you need to use it ...

To execute operations in a container, use the docker exec command. Sometimes this is called "entering the container" as all commands are executed inside the container. docker exec -it container_id bash or docker exec -it container_id /bin/sh And now you have a shell in your running...

To temporarily mark a file as ignored (pass file as parameter to alias) - type: unwatch = update-index --assume-unchanged To start tracking file again - type: watch = update-index --no-assume-unchanged To list all files that has been temporarily ignored - type: unwatched = "!git ls-fil...

There are two ways to achieve that, the first and most known is the following: docker attach --sig-proxy=false <container> This one literally attaches your bash to the container bash, meaning that if you have a running script, you will see the result. To detach, just type: Ctl-P Ctl-Q Bu...

Standard installation All Node.js binaries, installers, and source files can be downloaded here. You can download just the node.exe runtime or use the Windows installer (.msi), which will also install npm, the recommended package manager for Node.js, and configure paths. Installation by package m...

Users of homebrew can install gradle by running brew install gradle

Users of SdkMan can install Gradle by running: sdk install gradle Install specific version sdk list gradle sdk install gradle 2.14 Switch versions sdk use gradle 2.12

We plot a simple scatter plot using the builtin iris data set as follows: library(ggplot2) ggplot(iris, aes(x = Petal.Width, y = Petal.Length, color = Species)) + geom_point() This gives: