Tutorial by Examples: p

A frequent question about StackViews inside Scrollviews comes from ambiguous with/heigh alerts on interface builder. As this answer explained, it is necessary to: Add in the UIScrollView a UIView (the contentScrollView); In this contentScrollView, set top, bottom, left and right margins to 0 Se...

If you want users to upload files to your server you need to do a couple of security checks before you actually move the uploaded file to your web directory. The uploaded data: This array contains user submitted data and is not information about the file itself. While usually this data is generate...

""" A [GFF parser script][1] in Python for [www.VigiLab.org][2] Description: - That performs buffered reading, and filtering (see: @filter) of .GFF input file (e.g. "[./toy.gff][3]") to keep only rows whose field (column) values are equal to "transcript...

The MIDI Thru is simple and easy to test. When working properly you will be able to install your Arduino project between two MIDI devices, MIDI IN to MIDI OUT and you will be able to verify that the two device operate together. If you have the ability to measure latency, you will see an increase d...

For example, imagine a screen with 3 sections, laid out like this: The blue box might be given a margin of 4,4,0,0. The green box might be given a margin of 4,4,4,0. The purple box margin would be 4,4,4,4. Here's the XAML: (I'm using a grid to achieve the layout; but this design principle applies...

Sometimes Android's logcat is running infinitely with errors coming from some process not own by you, draining battery or just making it hard to debug your code. A convenient way to fix the problem without restarting the device is to locate and kill the process causing the problem. From Logcat 03...

You can use Scan or TryScan methods to look for specific messages in the queue and process them regardless of how many messages are before them. Both methods look at the messages in the queue in the order they arrived and will look for a specified message (up until optional timeout). In case there i...

Blocking Operation Example let loop = (i, max) => { while (i < max) i++ return i } // This operation will block Node.js // Because, it's CPU-bound // You should be careful about this kind of code loop(0, 1e+12) Non-Blocking IO Operation Example let i = 0 const step = max =...

So let's say again that you have the following model: public class Person { public int PersonId { get; set; } public string Name { get; set; } } public class Car { public int CarId { get; set; } public string LicensePlate { get; set; } } public class MyDemoContext : DbContext ...

Mapping one-to-one (when both sides are required) is also a tricky thing. Let's imagine how this could be represented with foreign keys. Again, a CarId in People that refers to CarId in Car, and a PersonId in Car that refers to the PersonId in People. Now what happens if you want to insert a car r...

And to finish off, let's briefly look at the case when both sides are optional. By now you should be really bored with these examples :), so I'm not going into the details and play with the idea of having two FK-s and the potential problems and warn you about the dangers of not enforcing these rule...

const http = require('http') const fs = require('fs') const zlib = require('zlib') http.createServer((request, response) => { const stream = fs.createReadStream('index.html') const acceptsEncoding = request.headers['accept-encoding'] let encoder = { hasEncoder ...

""" CannyTrackbar function allows for a better understanding of the mechanisms behind Canny Edge detection algorithm and rapid prototyping. The example includes basic use case. 2 of the trackbars allow for tuning of the Canny function and the other 2 help with understanding h...

So let's say you have two different entities, something like this: public class Person { public int PersonId { get; set; } public string Name { get; set; } } public class Car { public int CarId { get; set; } public string LicensePlate { get; set; } } public class MyDemoCon...

In the last example, you can see that EF figures out which column is the foreign key and where should it point to. How? By using conventions. Having a property of type Person that is named Person with a PersonId property leads EF to conclude that PersonId is a foreign key, and it points to the prima...

In the previous examples a car cannot exist without a person. What if you wanted the person to be optional from the car side? Well, it's kind of easy, knowing how to do one-to-many. Just change the PersonId in Car to be nullable: public class Car { public int CarId { get; set; } public s...

HERE Android Premium SDK samples Now available on Github! [https://github.com/heremaps/here-android-sdk-examples][1] HERE iOS Premium SDK samples Now available on Github! [https://github.com/heremaps/here-ios-sdk-examples][1] Please refer to the README.md on how to get started. Note the samples ...

As an example we want to set all string properties of a sample class class TestClass { val readOnlyProperty: String get() = "Read only!" var readWriteString = "asd" var readWriteInt = 23 var readWriteBackedStringProperty: String = "" ...

Let's define a grammar enabling us to perform additions, multiplications with the usage of parenthesis. To add more value to this example, we are going to compute the result of the arithmetic expression. Summary of the grammar: expression → times expression → times '+' expression times → elemen...

Suppose we want to know how many users have the same name. Let us create table users as follows: create table users( id serial, name varchar(8) unique, count int ); Now, we just discovered a new user named Joe and would like to take him into account. To achieve that, we need to d...