Tutorial by Examples: ed

To check if a required gem is installed, from within your code, you can use the following (using nokogiri as an example): begin found_gem = Gem::Specification.find_by_name('nokogiri') require 'nokogiri' .... <the rest of your code> rescue Gem::LoadError end However, this can ...

ScopedTypeVariables let you refer to universally quantified types inside of a declaration. To be more explicit: import Data.Monoid foo :: forall a b c. (Monoid b, Monoid c) => (a, b, c) -> (b, c) -> (a, b, c) foo (a, b, c) (b', c') = (a :: a, b'', c'') where (b'', c'') = (b <&g...

The code sample below shows one way to retrieve records from an MSSql Server in a background thread using FireDAC. Tested for Delphi 10 Seattle As written: The thread retrieves data using its own TFDConnection and TFDQuery and transfers the data to the form's FDQuery in a call to Sychronize...

The first element of sys.argv[0] is the name of the python file being executed. The remaining elements are the script arguments. # script.py import sys print(sys.argv[0]) print(sys.argv) $ python script.py => script.py => ['script.py'] $ python script.py fizz => script.py ...

In order to sort a query, instead of using findAll(), you should use findAllSorted(). RealmResults<SomeObject> results = realm.where(SomeObject.class) .findAllSorted("sortField", Sort.ASCENDING); Note: sort() returns a completely new ...

This is a nice trick to add a link to code, so it will be easy to jump to the code that issued the log. With the following code, this call: MyLogger.logWithLink("MyTag","param="+param); Will result in: 07-26...012/com.myapp D/MyTag: MyFrag:onStart(param=3) (MyFrag.java:236...

Current updates the branch on the remote repository that shares a name with the current working branch. git config push.default current Simple pushes to the upstream branch, but will not work if the upstream branch is called something else. git config push.default simple Upstream pushes to t...

Create a DATABASE. Note that the shortened word SCHEMA can be used as a synonym. CREATE DATABASE Baseball; -- creates a database named Baseball If the database already exists, Error 1007 is returned. To get around this error, try: CREATE DATABASE IF NOT EXISTS Baseball; Similarly, DROP DATA...

class ClassWithAReallyLongName { public: class Iterator { /* ... */ }; Iterator end(); }; Defining the member end with a trailing return type: auto ClassWithAReallyLongName::end() -> Iterator { return Iterator(); } Defining the member end without a trailing return type: Clas...

Example for searching just one user with a specific id, you should do: $options = ['limit' => 1]; $filter = ['_id' => new \MongoDB\BSON\ObjectID('578ff7c3648c940e008b457a')]; $query = new \MongoDB\Driver\Query($filter, $options); $cursor = $manager->executeQuery('database_name.collect...

Example for searching multiple users with the name "Mike": $filter = ['name' => 'Mike']; $query = new \MongoDB\Driver\Query($filter); $cursor = $manager->executeQuery('database_name.collection_name', $query); foreach ($cursor as $doc) { var_dump($doc); }

Given a local directory with the following contents: └── dir1 ├── subdir1 └── subdir2 We want to create the same subdir1, subdir2 under a new directory dir2, which does not exist yet. import os os.makedirs("./dir2/subdir1") os.makedirs("./dir2/subdir2") R...

All parameters specified after the first asterisk in the function signature are keyword-only. def f(*a, b): pass f(1, 2, 3) # TypeError: f() missing 1 required keyword-only argument: 'b' In Python 3 it's possible to put a single asterisk in the function signature to ensure that the rema...

Why an Editor Window? As you may have seen, you can do a lot of things in a custom inspector (if you don't know what a custom inspector is, check the example here : http://www.riptutorial.com/unity3d/topic/2506/extending-the-editor. But at one point you may want to implement a configuration panel, ...

It is possible to easily catch the exception without any try catch block. public class ListTest { private final List<Object> list = new ArrayList<>(); @Test(expected = IndexOutOfBoundsException.class) public void testIndexOutOfBoundsException() { list.get(0); } } ...

In Java, it's too "easy" to create many String instances which are not needed. That and other reasons might cause your program to have lots of Strings that the GC is busy cleaning up. Some ways you might be creating String instances: myString += "foo"; Or worse, in a loop or...

This is the advanced approach with example class FundsController < ApplicationController def index @funds = Fund.all_funds(current_user) end def show @fund = Fund.find(params[:id]) respond_to do |format| format.html format.pdf do pdf = FundsPdf....

Sometimes gotoAndStop() is called in the middle of the code that refers some frame-based properties. But, right after the frame is changed all links to properties that existed on the current frame are invalidated, so any processing that involves them should be immediately terminated. There are two ...

Without a try catch block, undefined functions will throw errors and stop execution: undefinedFunction("This will not get executed"); console.log("I will never run because of the uncaught error!"); Will throw an error and not run the second line: // Uncaught ReferenceError:...

Think of the mediator pattern as the flight control tower that controls planes in the air: it directs this plane to land now, the second to wait, and the third to take off, etc. However no plane is ever allowed to talk to its peers. This is how mediator works, it works as a communication hub among ...