Tutorial by Examples: ch

roslaunch is an important tool that manages the start and stop of ROS nodes. It takes one or more "*.launch" files as arguments. For this example, I will refer to the following (as asked in this question), so how can we execute those commands consecutively & automatically : roscd ste...

Objective-C //Checking for 3-D Touch availability if ([self.traitCollection respondsToSelector:@selector(forceTouchCapability)] && (self.traitCollection.forceTouchCapability == UIForceTouchCapabilityAvailable)) { [self registerForPreviewingWithDelegate:self sourceVie...

Linear search is a simple algorithm. It loops through items until the query has been found, which makes it a linear algorithm - the complexity is O(n), where n is the number of items to go through. Why O(n)? In worst-case scenario, you have to go through all of the n items. It can be compared to l...

Given a money system, is it possible to give an amount of coins and how to find a minimal set of coins corresponding to this amount. Canonical money systems. For some money system, like the ones we use in the real life, the "intuitive" solution works perfectly. For example, if the diffe...

A SwitchCell is a Cell that combines the capabilities of a Label and an on-off switch. A SwitchCell can be useful for turning on and off functionality, or even user preferences or configuration options. XAML <SwitchCell Text="Switch It Up!" /> Code var switchCell = new Switch...

To disable synchronization context you should call the ConfigureAwait method: async Task() Foo() { await Task.Run(() => Console.WriteLine("Test")); } . . . Foo().ConfigureAwait(false); ConfigureAwait provides a means to avoid the default SynchronizationContext capturi...

Objective-C //Displays the country pickerView with black background and white text [self. countryPicker setValue:[UIColor whiteColor] forKey:@"textColor"]; [self. countryPicker setValue:[UIColor blackColor] forKey:@"backgroundColor"]; Swift let color1 = UIColor(colorLitera...

This is a porting of set up sourced from DigitalOcean's tutorial of How To Serve Flask Applications with uWSGI and Nginx on Ubuntu 14.04 and some useful git resources for nginx servers. Flask Application This tutorial assume you use Ubuntu. locate var/www/ folder. Create your web app folder m...

First off, let's assume this is your initial model, inside an application called discography: from django.db import models class Album(models.Model): name = models.CharField(max_length=255) artist = models.CharField(max_length=255) Now, you realize that you want to use a ForeignKey ...

We have a DataListComponent that shows a data we pull from a service. DataListComponent also has a PagerComponent as it's child. PagerComponent creates page number list based on total number of pages it gets from the DataListComponent. PagerComponent also lets the DataListComponent know when user c...

Consider this example: private void button1_Click(object sender, EventArgs e) { label1.Text = RunTooLong(); } This method will freeze UI application until the RunTooLong will be completed. The application will be unresponsive. You can try run inner code asynchronously: private void butt...

Viewchild offers one way interaction from parent to child. There is no feedback or output from child when ViewChild is used. We have a DataListComponent that shows some information. DataListComponent has PagerComponent as it's child. When user makes a search on DataListComponent, it gets a data fro...

import { NgModule, CUSTOM_ELEMENTS_SCHEMA } from '@angular/core'; import { CommonModule } from '@angular/common'; import { AboutComponent } from './about.component'; @NgModule({ imports: [ CommonModule ], declarations: [ AboutComponent ], exports: [ AboutComponent ], schemas...

This is an example of using until/retries/delay to implement an alive check for a webapp that is starting up. It assumes that there will be some period of time (up to 3 minutes) where the webapp is refusing socket connections. After that, it checks the /alive page for the word "OK". It als...

select * from dict

XML <Deborah> <address>Dark world</address> <master>Babadi</master> <ID>#0</ID> <colour>red</colour> <side>evil</side> </Deborah> XPATH boolean(/Deborah/master/text()) OR string(/Deborah/master...

XML <Dobby> <address>Hogwartz</address> <master></master> <colour>wheatish</colour> <side>all good</side> </Dobby> XPATH boolean(/Dobby/master/text()) OR string(/Dobby/master) != '' OUTPUT false

When you compiled and loaded the code in the three examples before (ODEs in compiled languages - definition in R, ODEs in compiled languages - definition in C and ODEs in compiled languages - definition in fortran) you are able to run a benchmark test. library(microbenchmark) R <- function(){...

MailMessage represents mail message which can be sent further using SmtpClient class. Several attachments (files) can be added to mail message. using System.Net.Mail; using(MailMessage myMail = new MailMessage()) { Attachment attachment = new Attachment(path); myMail.Attachments.Add...

GCobol >>SOURCE FORMAT IS FIXED *> *************************************************************** *> Purpose: Demonstration of the SEARCH verb *> Tectonics: cobc -x searchlinear.cob *> *************************************************************** ...