Tutorial by Examples: s

CASE's shorthand variant evaluates an expression (usually a column) against a series of values. This variant is a bit shorter, and saves repeating the evaluated expression over and over again. The ELSE clause can still be used, though: SELECT Id, ItemId, Price, CASE Price WHEN 5 THEN 'CHEAP' ...

The struct template std::pair can bundle together exactly two return values, of any two types: #include <utility> std::pair<int, int> foo(int a, int b) { return std::make_pair(a+b, a-b); } With C++11 or later, an initializer list can be used instead of std::make_pair: C++11 ...

void Main() { unsafe { int[] a = {1, 2, 3}; fixed(int* b = a) { Console.WriteLine(b[4]); } } } Running this code creates an array of length 3, but then tries to get the 5th item (index 4). On my machine, this printed 1910457872, bu...

Classes are identifiers for the elements that they are assigned to. Use the class attribute to assign a class to an element. <div class="example-class"></div> To assign multiple classes to an element, separate the class names with spaces. <div class="class1 class2&...

You can apply any kind of additional processing to the output by passing a callable to ob_start(). <?php function clearAllWhiteSpace($buffer) { return str_replace(array("\n", "\t", ' '), '', $buffer); } ob_start('clearAllWhiteSpace'); ?> <h1>Lorem Ipsum&l...

Variables you have provided in your view context can be accessed using double-brace notation: In your views.py: class UserView(TemplateView): """ Supply the request user object to the template """ template_name = "user.html" def get_context_data...

The datetime module contains three primary types of objects - date, time, and datetime. import datetime # Date object today = datetime.date.today() new_year = datetime.date(2017, 01, 01) #datetime.date(2017, 1, 1) # Time object noon = datetime.time(12, 0, 0) #datetime.time(12, 0) # Curr...

C++11 for loops can be used to iterate over the elements of a iterator-based range, without using a numeric index or directly accessing the iterators: vector<float> v = {0.4f, 12.5f, 16.234f}; for(auto val: v) { std::cout << val << " "; } std::cout <<...

This uses the Dropbox Python SDK to upload a file to the Dropbox API from the local file as specified by file_path to the remote path as specified by dest_path. It also chooses whether or not to use an upload session based on the size of the file: f = open(file_path) file_size = os.path.getsize(fi...

Useful for simple animations, the CSS transition property allows number-based CSS properties to animate between states. Example .Example{ height: 100px; background: #fff; } .Example:hover{ height: 120px; background: #ff0000; } View Result By default, hovering over an...

When creating animations and other GPU-heavy actions, it's important to understand the will-change attribute. Both CSS keyframes and the transition property use GPU acceleration. Performance is increased by offloading calculations to the device's GPU. This is done by creating paint layers (parts of...

For multi-stage CSS animations, you can create CSS @keyframes. Keyframes allow you to define multiple animation points, called a keyframe, to define more complex animations. Basic Example In this example, we'll make a basic background animation that cycles between all colors. @keyframes rainbow...

Using Item Sales Table from Example Database, let us calculate and show the total Quantity we sold of each Product. This can be easily done with a group by, but lets assume we to 'rotate' our result table in a way that for each Product Id we have a column. SELECT [100], [145] FROM (SELECT ItemI...

Setting a filter applies to all channels that you will subscribe to from that particular client. This client filter excludes messages that have this subscriber's UUID set at the sender's UUID: NSString *expression = [NSString stringWithFormat:@"(uuid != '%@'", se...

This example uses the Dropbox .NET library to try to get the metadata for an item at a particular path, and checks for a NotFound error: try { var metadata = await this.client.Files.GetMetadataAsync("/non-existant path"); Console.WriteLine(metadata.Name); } catch (Dropbox.Api.A...

Constructor injection is the safest way of injecting dependencies that a whole class depends upon. Such dependencies are often referred to as invariants, since an instance of the class cannot be created without supplying them. By requiring the dependency to be injected at construction, it is guara...

Whilst extracting dependencies out of your code so that they can be injected makes your code easier to test, it pushes the problem further up the hierarchy and can also result in objects that are difficult to construct. Various dependency injection frameworks / Inversion of Control Containers have ...

If you want to squash the previous x commits into a single one, you can use the following commands: git reset --soft HEAD~x git commit Replacing x with the number of previous commits you want to be included in the squashed commit. Mind that this will create a new commit, essentially forgetting...

Commits can be squashed during a git rebase. It is recommended that you understand rebasing before attempting to squash commits in this fashion. Determine which commit you would like to rebase from, and note its commit hash. Run git rebase -i [commit hash]. Alternatively, you can type HE...

A controller is a basic structure used in Angular to preserve scope and handle certain actions within a page. Each controller is coupled with an HTML view. Below is a basic boilerplate for an Angular app: <!DOCTYPE html> <html lang="en" ng-app='MyFirstApp'> <head...