Tutorial by Examples: id

In medical imaging, spectroscopy, image processing, cryptography and other areas of science and engineering it is often the case that one wishes to compute multidimensional Fourier transforms of images. This is quite straightforward in Matlab: (multidimensional) images are just n-dimensional matrice...

This method just returns the first argument. var res1 = _.identity(10, 20); // res1 now is 10 var res2 = _.identity("hello", "world"); // res2 now is "hello" What does _.identity mean in lodash documentation? This method is used throughout lodash documentation...

You can test whether a point is inside a rectangle using Rectangle.containsPoint(): var point:Point = new Point(5, 5); var rectangle:Rectangle = new Rectangle(0, 0, 10, 10); var contains:Boolean = rectangle.containsPoint(point); // true

Any time you instantiate a class that Implements IDisposable, you should call .Dispose1 on that class when you have finished using it. This allows the class to clean up any managed or unmanaged dependencies that it may be using. Not doing this could cause a memory leak. The Using keyword ensures th...

Range sliders provide 2 draggable handles to select numeric values. The slider's initialization must provide a range option set to true to create a range slider: <script> $(function() { $( "#range-slider" ).slider({ range: true }); }); </script> &lt...

The slider provides an event called slide that will trigger whenever the mouse moves during a slider handle drag. This function holds a reference to the slide event and a reference to the slider ui object. The ui object holds a jQuery object for the handle being moved and the value(s) of the slide...

When a runtime error occurs, good code should handle it. The best error handling strategy is to write code that checks for error conditions and simply avoids executing code that results in a runtime error. One key element in reducing runtime errors, is writing small procedures that do one thing. Th...

library(caret) # for dummyVars library(RCurl) # download https data library(Metrics) # calculate errors library(xgboost) # model ############################################################################### # Load data from UCI Machine Learning Repository (http://archive.ics.uci.edu/ml/data...

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""" ================================================================================ CREATE A 2 BY 2 GRID OF SUB-PLOTS WITHIN THE SAME FIGURE. ================================================================================ """ import matplotlib.pyplot as plt ...

foldMap maps each element of the Foldable structure to a Monoid, and then combines them into a single value. foldMap and foldr can be defined in terms of one another, which means that instances of Foldable need only give a definition for one of them. class Foldable t where foldMap :: Monoid m...

The reserved word "void" is an alias of System.Void type, and has two uses: Declare a method that doesn't have a return value: public void DoSomething() { // Do some work, don't return any value to the caller. } A method with a return type of void can still have the return ...

/* Callback for JVMTI_EVENT_VM_INIT */ static void JNICALL vm_init(jvmtiEnv* jvmti, JNIEnv* env, jthread thread) { jint runtime_version; jvmti->GetVersionNumber(&runtime_version); stdout_message("JVMTI Version: %d\n", runtime_verision); } /* Agent_OnLoad() is ca...

In addition to the concept of column units, Bootstrap has different breakpoints or grid sizes known as tiers. The Bootstrap 3 grid has four (4) tiers to accomodate different screen (or viewport) widths. The Bootstrap 3 tiers are xs, sm, md, and lg. Bootstrap’s grid columns are identified by differen...

Sometimes, you want your threads to simultaneously share data. When this happens it is important to be aware of the code and lock any parts that could go wrong. A simple example of two threads counting is shown below. Here is some dangerous (incorrect) code: using System.Threading; class MainCl...

The Firebase Realtime Database is schemaless. This makes it easy to change things as you develop, but once your app is ready to distribute, it's important for data to stay consistent. The rules language includes a .validate rule which allows you to apply validation logic using the same expressions u...

With more and more battery optimizations being put into the Android system over time, the methods of the AlarmManager have also significantly changed (to allow for more lenient timing). However, for some applications it is still required to be as exact as possible on all Android versions. The follow...

Another use of RODBC is in connecting with SQL Server Management Database. We need to specify the 'Driver' i.e. SQL Server here, the database name "Atilla" and then use the sqlQuery to extract either the full table or a fraction of it. library(RODBC) cn <- odbcDriverConnect(connect...

The first step to logging is simply to run Meteor from the shell, and you'll get the server logs in the command console. meteor The next step is to pipe the contents of std_out and std_err to a logfile, like so: meteor > my_app_log.log 2> my_app_err.log

Once you have your server side logging in place, it's time to hop over to the client side. If you haven't explored the console API, be prepared for a treat. There's actually all sorts of things that you can do with the built in Console API that's native to every Chrome and Safari installation. So mu...