Tutorial by Examples: x

By default, plot() creates a new figure each time it is called. It is possible to plot on an existing axis by passing the ax parameter. plt.figure() # create a new figure ax = plt.subplot(121) # create the left-side subplot df1.plot(ax=ax) # plot df1 on that subplot ax = plt.subplot(122) # c...

All integers or pointers can be used in an expression that is interpreted as "truth value". int main(int argc, char* argv[]) { if (argc % 4) { puts("arguments number is not divisible by 4"); } else { puts("argument number is divisible by 4"); } ... ...

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 PHP execution operator consists of backticks (``) and is used to run shell commands. The output of the command will be returned, and may, therefore, be stored in a variable. // List files $output = `ls`; echo "<pre>$output</pre>"; Note that the execute operator and sh...

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 ...

For queries, Realm provides the realmResults.asObservable() method. Observing results is only possible on looper threads (typically the UI thread). For this to work, your configuration must contain the following realmConfiguration = new RealmConfiguration.Builder(context) // ...

Sometimes you need to determine the target of a symlink. os.readlink will do this: print(os.readlink(path_to_symlink))

A lambda closure is created when a lambda expression references the variables of an enclosing scope (global or local). The rules for doing this are the same as those for inline methods and anonymous classes. Local variables from an enclosing scope that are used within a lambda have to be final. Wit...

To improve performance one might want to add indexes to columns ALTER TABLE TABLE_NAME ADD INDEX `index_name` (`column_name`) altering to add composite (multiple column) indexes ALTER TABLE TABLE_NAME ADD INDEX `index_name` (`col1`,`col2`)

A common workflow for using Git LFS is to declare which files are intercepted through a rules-based system, just like .gitignore files. Much of time, wildcards are used to pick certain file-types to blanket track. e.g. git lfs track "*.psd" When a file matching the above pattern is adde...

7.0 OrElse Sub Main() Dim elements As List(Of Integer) = Nothing Dim average As Double = AverageElementsOrElse(elements) Console.WriteLine(average) ' Writes 0 to Console Try 'Throws ArgumentNullException average = AverageElementsOr(elements) Catch ex ...

auto can also cause problems where expression templates come into play: auto mult(int c) { return c * std::valarray<int>{1}; } auto v = mult(3); std::cout << v[0]; // some value that could be, but almost certainly is not, 3. The reason is that operator* on valarray gives yo...

Given the following XML document: <documentation> <tags> <tag name="Java"> <topic name="Regular expressions"> <example>Matching groups</example> <example>Escaping metacharacter...

Sometimes specific instances of data should be used. Recreation is not desired and referencing static data would have a code smell. It is possible to specify a XmlAdapter instance the Unmarshaller should use, which allows the user to use XmlAdapters with no zero-arg constructor and/or pass data to ...

On calling, an application chooser dialog will appear and by selecting an application you can share your content with it. For calling use this line of code in your program class: share(context, "This is a test message", "Test Subject") Function's definition: public static v...

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); } } ...

If you just want to get data, but not modify anything, you can turn off change tracking and proxy creation. This will improve your performance and also prevent lazy loading. Bad Example: using(var context = new Context()) { return await context.Set<MyEntity>().ToListAsync().ConfigureAw...

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....

You need to add Gem and PDF MIME:Type inside mime_types.rb as we need to notify rails about PDF mime type. After that we can generate Pdf with Prawn in following basic ways This is the basic assignment pdf = Prawn::Document.new pdf.text "Hello World" pdf.render_file "assignment.p...

A lambda can only have a trailing return type; the leading return type syntax is not applicable to lambdas. Note that in many cases it is not necessary to specify a return type for a lambda at all. struct Base {}; struct Derived1 : Base {}; struct Derived2 : Base {}; auto lambda = [](bool b) -&g...