Tutorial by Examples: co

F() expressions can be used to execute arithmetic operations (+, -, * etc.) among model fields, in order to define an algebraic lookup/connection between them. Let model be: class MyModel(models.Model): int_1 = models.IntegerField() int_2 = models.IntegerField() Now lets assum...

In a terminal run brew install maven Once the install is over check that maven works correctly with mvn -v. The output should look something like: Apache Maven 3.3.9 Maven home: /usr/local/Cellar/maven/3.3.9/libexec Java version: 1.8.0_121, vendor: Oracle Corporation Java home: /Library/Ja...

In the new Angular framework, Components are the main building blocks that compose the user interface. So one of the first steps that helps an AngularJS app to be migrated to the new Angular is to refactor it into a more component-oriented structure. Components were also introduced in the old Angu...

This snippet will list all the filenames of a zip archive. The filenames are relative to the zip root. using (FileStream fs = new FileStream("archive.zip", FileMode.Open)) using (ZipArchive archive = new ZipArchive(fs, ZipArchiveMode.Read)) { for (int i = 0; i < archive.Entries....

Decoding the chunks of a PNG file demonstrates Okio in practice. private static final ByteString PNG_HEADER = ByteString.decodeHex("89504e470d0a1a0a"); public void decodePng(InputStream in) throws IOException { try (BufferedSource pngSource = Okio.buffer(Okio.source(in))) { Byt...

To see you unit tests go to Test -> Windows -> Code Coverage Results (Figure 1) It will open the following window (Figure 2) The window is now empty Go to the Test menu -> Analyze Code Coverage (Figure 3) The tests will now be run as well (See the results in the T...

The nil-coalescing operator <OPTIONAL> ?? <DEFAULT VALUE> unwraps the <OPTIONAL> if it contains a value, or returns <DEFAULT VALUE> if is nil. <OPTIONAL> is always of an optional type. <DEFAULT VALUE> must match the type that is stored inside <OPTIONAL>. T...

We can perform a GROUP BY ... COUNT or a GROUP BY ... SUM SQL equivalent queries on Django ORM, with the use of annotate(), values(), order_by() and the django.db.models's Count and Sum methods respectfully: Let our model be: class Books(models.Model): title = models.CharField() ...

Lets assume that we have a complex api, with many generic views and some generic viewsets. We want to enable PageNumberPagination to every view, except one (either generic view or viewset, does not make a difference) for which we want a customized case of LimitOffsetPagination. To achieve that we n...

A generalization of std::condition_variable, std::condition_variable_any works with any type of BasicLockable structure. std::cv_status as a return status for a condition variable has two possible return codes: std::cv_status::no_timeout: There was no timeout, condition variable was notified st...

Function definition: def run_training(train_X, train_Y): Inputs variables: X = tf.placeholder(tf.float32, [m, n]) Y = tf.placeholder(tf.float32, [m, 1]) Weight and bias representation W = tf.Variable(tf.zeros([n, 1], dtype=np.float32), name="weight") b = tf.Variable(tf.zeros([...

Laravel Scout - Laravel Scout provides a simple, driver-based solution for adding full-text search to your Eloquent models. Laravel Passport - API authentication without a headache. Passport is an OAuth2 server that's ready in minutes. Homestead - The official Laravel development environment. Po...

Requirements: Add following references to the project: Microsoft ActiveX Data Objects 2.8 Library Microsoft ActiveX Data Objects Recordset 2.8 Library Declare variables Private mDataBase As New ADODB.Connection Private mRS As New ADODB.Recordset Private mCmd As New ADODB.Command...

First get the Configuration File for Sign-in from Open link below [https://developers.google.com/identity/sign-in/android/start-integrating][1] click on get A configuration file Enter App name And package name and click on choose and configure services provide SHA1 Enable google SIGNIN and g...

In your sign-in activity's onCreate method, configure Google Sign-In to request the user data required by your app. GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN) .requestEmail() .build(); create a GoogleApiClient object wi...

Create new instance of UISegmentedControl filled with 3 items (segments): let mySegmentedControl = UISegmentedControl (items: ["One", "Two", "Three"]) Setup frame; mySegmentedControl.frame = CGRect(x: 0.0, y: 0.0, width: 300, height: 50) Make default s...

For those who haven't played with these two designs, the scope of lazy and eager is within a specific Session of SessionFactory. Eager loads everything instantly, means there is no need to call anything for fetching it. But lazy fetch usually demands some action to retrieve mapped collection/object....

function noOfLooping(m,n) { if(m > n) { smallestValue = n; } else { smallestValue = m; } if(smallestValue % 2 == 0) { return smallestValue/2; } else { return (smallestValue+1)/2; } } function squarePrint(m,n) { v...

So the good news is that Apple kindly includes a Ruby interpreter. Unfortunately, it tends not to be a recent version: $ /usr/bin/ruby -v ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin16] If you have Homebrew installed, you can get the latest Ruby with: $ brew install ruby...

Integration to open database using password. -(void)checkAndOpenDB{ sqlite3 *db; NSString *strPassword = @"password"; if (sqlite3_open_v2([[databaseURL path] UTF8String], &db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, NULL) == SQLITE_OK) { const cha...