Tutorial by Examples: d

Create a DataFrame of random numbers: import numpy as np import pandas as pd # Set the seed for a reproducible sample np.random.seed(0) df = pd.DataFrame(np.random.randn(5, 3), columns=list('ABC')) print(df) # Output: # A B C # 0 1.764052 0.400157 0.9787...

As Handlers are used to send Messages and Runnables to a Thread's message queue it's easy to implement event based communication between multiple Threads. Every Thread that has a Looper is able to receive and process messages. A HandlerThread is a Thread that implements such a Looper, for example th...

Naming Convention Notifications are identified by global NSString objects whose names are composed in this way: Name of associated class + Did | Will + UniquePartOfName + Notification For example: NSApplicationDidBecomeActiveNotification NSWindowDidMiniaturizeNotification NSTextViewDidChange...

Swift let userInfo: [String: AnyObject] = ["someKey": myObject] NSNotificationCenter.defaultCenter().postNotificationName("TestNotification", object: self, userInfo: userInfo) Objective-C NSDictionary *userInfo = [NSDictionary dictionaryWithObject:myObject forKey:@"som...

g$ The above matches one letter (the letter g) at the end of a string in most regex engines (not in Oniguruma, where the $ anchor matches the end of a line by default, and the m (MULTILINE) modifier is used to make a . match any characters including line break characters, as a DOTALL modifier in ...

my $filename = '/path/to/file'; open my $fh, '<', $filename or die "Failed to open file: $filename"; # You can then either read the file one line at a time... while(chomp(my $line = <$fh>)) { print $line . "\n"; } # ...or read whole file into an arra...

This is useful when you didn't store the PID from a previous command iex(1)> self() #PID<0.138.0> iex(2)> pid("0.138.0") #PID<0.138.0> iex(3)> pid(0, 138, 0) #PID<0.138.0>

You can broadcast more complex messages by serializing the payload before you publish it: // definition of a message public class ChatMessage { public Guid Id { get; set; } public string User { get; set; } public string Text { get; set; } } // grab an instance of an ISubscriber...

StackExchange.Redis also supports sending bytes over the pub/sub channel, here we use protobuf-net to serialize our message to a byte array before sending it: // definition of a message (marked up with Protobuf attributes) [ProtoContract] public class ChatMessage { [ProtoMember(1)] pub...

One (or two) of the coolest new features in recent Xcode releases are the IBInspectable properties and IBDesignable UIViews. These have nothing to do with the functionality of your application but instead impact the developer experience in Xcode. The goal is to be able to visually inspect custom v...

If you want to get rid of the username field and use email as unique user identifier, you will have to create a custom User model extending AbstractBaseUser instead of AbstractUser. Indeed, username and email are defined in AbstractUser and you can't override them. This means you will also have to r...

You can specify a column that contains dates so pandas would automatically parse them when reading from the csv pandas.read_csv('data_file.csv', parse_dates=['date_column'])

When applied to a class, the sealed modifier prevents other classes from inheriting from it. class A { } sealed class B : A { } class C : B { } //error : Cannot derive from the sealed class When applied to a virtual method (or virtual property), the sealed modifier prevents this method (proper...

This example demonstrates that HTTP is a text-based Internet communications protocol, and shows a basic HTTP request and the corresponding HTTP response. You can use Telnet to manually send a minimal HTTP request from the command line, as follows. Start a Telnet session to the web server www.e...

FlashDevelop is a multi-platform open source IDE created in 2005 for Flash developers. With no cost, it's a very popular way to get started developing with AS3. To Install FlashDevelop: Download The Installation File and run the installer Once installation is complete, run FlashDevelop. On the ...

Selenium is a set of tools designed to automate browsers. It is commonly used for web application tests across multiple platforms. There are a few tools available under the Selenium umbrella, such as Selenium WebDriver(ex-Selenium RC), Selenium IDE and Selenium Grid. WebDriver is a remote control i...

A VectorDrawable should consist of at least one <path> tag defining a shape <vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="24dp" android:height="24dp" android:viewportWidth="24.0" android:viewpor...

An AnimatedVectorDrawable requires at least 3 components: A VectorDrawable which will be manipulated An objectAnimator which defines what property to change and how The AnimatedVectorDrawable itself which connects the objectAnimator to the VectorDrawable to create the animation The following...

In AS3, display assets are not visible until they are added to the Display List. The AIR/Flash runtime has a hierarchical display structure (parent child relationship where children can have their own children), with the stage being the top level parent. To add something to the display list, you u...

Swift let frame = CGRect(x: 0, y: 0, width: 100, height: 100) let textField = UITextField(frame: frame) Objective-C CGRect *frame = CGRectMake(0, 0, 100, 100); UITextField *textField = [[UITextField alloc] initWithFrame:frame]; Interface Builder You can also add a UITextField to a storybo...