Tutorial by Examples: ai

When we have two separate array and we want to make key value pair from that two array, we can use array's reduce function like below: var columns = ["Date", "Number", "Size", "Location", "Age"]; var rows = ["2001", "5", "B...

Like lists and tuples, you can include a trailing comma in your dictionary. role = {"By day": "A typical programmer", "By night": "Still a typical programmer", } PEP 8 dictates that you should leave a space between the trailing comma and the closi...

This query selects all books with any rating less than three. bad_books = Books.objects.filter(ratings_range__contains=(1, 3))

This query gets all books with ratings greater than or equal to zero and less than six. all_books = Book.objects.filter(ratings_range_contained_by=(0, 6))

Three methods are provided that offer the ability to strip leading and trailing characters from a string: str.strip, str.rstrip and str.lstrip. All three methods have the same signature and all three return a new string object with unwanted characters removed. str.strip([chars]) str.strip acts o...

trait Hello { public function sayHello() { echo 'Hello '; } } trait World { public function sayWorld() { echo 'World'; } } class MyHelloWorld { use Hello, World; public function sayExclamationMark() { echo '!'; } } $o = new My...

Firebase Authentication allows the users of your app to sign-in with social providers or their email+password. But what if you want to store additional information about a user, beyond what Firebase Authentication allows you to specify? Or what if you want to display a list of the users in your app...

Pass a dict object to field_name__contains as a keyword argument. Catalog.objects.filter(titles__contains={ 'Pro Git': 'Scott Chacon and Ben Straub'}) Equivalent to the SQL operator `@>`.

The when-statement is an alternative to an if-statement with multiple else-if-branches: when { str.length == 0 -> print("The string is empty!") str.length > 5 -> print("The string is short!") else -> print("The string is long!") ...

You can generate a rails migration file from the terminal using the following command: rails generate migration NAME [field[:type][:index] field[:type][:index]] [options] For a list of all the options supported by the command, you could run the command without any arguments as in rails generate ...

Higher-order functions can be used to ensure that system resources are disposed, even when a treatment raises an exception. The pattern used by with_output_file allows a clean separation of concerns: the higher-order with_output_file functions takes care of managing the system resources bound to fi...

The ls command has several options that can be used together to show more information. Details/Rights The l option shows the file permissions, size, and last modified date. So if the root directory contained a dir called test and a file someFile the command: user@linux-computer:~$ ls -l Would ...

The main content of a document. <!-- header & nav here --> <div role="main"> <p>Lorem ipsum...</p> </div> <!-- footer here -->

import 'dart:async'; Future main() async { var value = await _waitForValue(); print("Here is the value: $value"); //since _waitForValue() returns immediately if you un it without await you won't get the result var errorValue = "not finished yet"; _waitForValue()...

Before C++17, a function typically represented failure in one of several ways: A null pointer was returned. e.g. Calling a function Delegate *App::get_delegate() on an App instance that did not have a delegate would return nullptr. This is a good solution for objects that have been dynamicall...

Large fluent assertions do become harder to read, but when combined with classes that have good implementations of ToString(), they can generate very useful error messages. [Test] public void AdvancedContraintsGiveUsefulErrorMessages() { Assert.That(actualCollection, Has .Count.Equa...

The List.fold_left and List.fold_right functions are higher-order functions that implement the outer logic of list aggregation. Aggregating a list, sometimes also referred to as reducing a list, means computing a value derived from the sequential inspection of all items in that list. The documenta...

Holy Grail layout is a layout with a fixed height header and footer, and a center with 3 columns. The 3 columns include a fixed width sidenav, a fluid center, and a column for other content like ads (the fluid center appears first in the markup). CSS Flexbox can be used to achieve this with a very s...

A simple example on how to read a UTF text file synchronously. import flash.filesystem.File; import flash.filesystem.FileMode; import flash.filesystem.FileStream; //First, get a reference to the file you want to load var myFile:File = File.documentsDirectory.resolvePath("lifestory.txt&...

To generate a new mailer, enter the following command rails generate mailer PostMailer This will generate a blank template file in app/mailers/post_mailer.rb named PostMailer class PostMailer < ApplicationMailer end Two layout files will also be generated for the email view, one for the...