Tutorial by Examples: ti

The role of placeholders in "enter" selections

What is an enter selection? In D3.js, when one binds data to DOM elements, three situations are possible: The number of elements and the number of data points are the same; There are more elements than data points; There are more data points than elements; In the situation #3, all the data ...

d3.js • Selections

List iteration: foreach

foreach varlist1 list1 ?varlist2 list2 ...? body foreach is a powerful control structure that allows looping over a list or multiple lists. set alpha [list a b c d e f] foreach {key} $alpha { puts "key: $key" } Multiple variable names may be specified. set alphaindexes [list a ...

tcl • Control Structures

Message Propagation with Singleton Class

Instances never contain a method they only carry data. However we can define a singleton class for any object including an instance of a class. When a message is passed to an object (method is called) Ruby first checks if a singleton class is defined for that object and if it can reply to that mess...

Ruby Language • Singleton Class

Quoting

In the Tcl language in many cases, no special quoting is needed. These are valid strings: abc123 4.56e10 my^variable-for.my%use The Tcl language splits words on whitespace, so any literals or strings with whitespace should be quoted. There are two ways to quote strings. With braces and with...

tcl • Tcl Language Constructs

DecimalPropertyConvention

By default Entity Framework maps decimal properties to decimal(18,2) columns in database tables. public class Box { public int Id { set; get; } public decimal Length { set; get; } public decimal Width { set; get; } public decimal Height { set; get; } } We can change the p...

Entity Framework • Code First Conventions

Product collection - with attributes

//all attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('*'); //specific attributes $collection = Mage::getModel('catalog/product') ->getCollection() ->addAttributeToSelect('name'); //certain attributes are special...

magento • Get Products from Database

Primitive to Primitive conversion table

ValueConverted To StringConverted To NumberConverted To Booleanundefinded"undefined"NaNfalsenull"null"0falsetrue"true"1false"false"0NaN"NaN"false"" empty string0false" "0true"2.4" (numeric)2.4true"test" (non nu...

JavaScript • Variable coercion/conversion

Deleting a derived object via a pointer to a base class that doesn't have a virtual destructor.

class base { }; class derived: public base { }; int main() { base* p = new derived(); delete p; // The is undefined behavior! } In section [expr.delete] §5.3.5/3 the standard says that if delete is called on an object whose static type does not have a virtual destructor: if the...

C++ • Undefined Behavior

Avoiding duplication of code in const and non-const getter methods.

In C++ methods that differs only by const qualifier can be overloaded. Sometimes there may be a need of two versions of getter that return a reference to some member. Let Foo be a class, that has two methods that perform identical operations and returns a reference to an object of type Bar: class ...

C++ • const keyword

When to use a Static variable

A Static variable declared locally is not destructed and does not lose its value when the Sub procedure is exited. Subsequent calls to the procedure do not require re-initialization or assignment although you may want to 'zero' any remembered value(s). These are particularly useful when late bindin...

VBA • Declaring Variables

Animate at a specified time (an animated clock)

This example animates a clock showing the seconds as a filled wedge Annotated Code: <!doctype html> <html> <head> <style> body{ background-color:white; } #canvas{border:1px solid red; } </style> <script> window.onload=(function(){ // canva...

html5-canvas • Animation

Use requestAnimationFrame() NOT setInterval() for animation loops

requestAnimationFrame is similar to setInterval, it but has these important improvements: The animation code is synchronized with display refreshes for efficiency The clear + redraw code is scheduled, but not immediately executed. The browser will execute the clear + redraw code only when the d...

html5-canvas • Animation

Don't draw animations in your event handlers (a simple sketch app)

During mousemove you get flooded with 30 mouse events per second. You might not be able to redraw your drawings at 30 times per second. Even if you can, you're probably wasting computing power by drawing when the browser is not ready to draw (wasted == across display refresh cycles). Therefore it m...

html5-canvas • Animation

Runtime Code Generation

<#@ template language="C#" #> //Language of your project <#@ assembly name="System.Core" #> <#@ import namespace="System.Linq" #> <#@ import namespace="System.Text" #> <#@ import namespace="System.Collections.Generic" ...

C# Language • T4 Code Generation

Installation or Setup

Detailed instructions on getting netty set up or installed.

netty • Getting started with netty

Dialects of Lisp and their implementations

Invented by John McCarthy around 1958, Lisp (List Processor) has continued to grow into an entire family of languages. Since StackOverflow is more about practical programming problems, typically problems will involve actual Lisp dialects or derived languages and their implementations. Problems that...

lisp • Getting started with lisp

Testing all commits during rebase

Before making a pull request, it is useful to make sure that compile is successful and tests are passing for each commit in the branch. We can do that automatically using -x parameter. For example: git rebase -i -x make will perform the interactive rebase and stop after each commit to execute mak...

Git • Rebasing

Creating a bidirectional LSTM

import tensorflow as tf dims, layers = 32, 2 # Creating the forward and backwards cells lstm_fw_cell = tf.nn.rnn_cell.BasicLSTMCell(dims, forget_bias=1.0) lstm_bw_cell = tf.nn.rnn_cell.BasicLSTMCell(dims, forget_bias=1.0) # Pass lstm_fw_cell / lstm_bw_cell directly to tf.nn.bidrectional_rnn ...

tensorflow • Creating RNN, LSTM and bidirectional RNN/LSTMs with TensorFlow

Creating a custom analyzer

Most analysis customization is in the createComponents class, where the Tokenizer and TokenFilters are defined. CharFilters can be added in the initReader method. Analyzer analyzer = new Analyzer() { @Override protected Reader initReader(String fieldName, Reader reader) { retu...

lucene • Analysis

Iterating manually through analyzed tokens

TokenStream stream = myAnalyzer.tokenStream("myField", textToAnalyze); stream.addAttribute(CharTermAttribute.class); stream.reset(); while(stream.incrementToken()) { CharTermAttribute token = stream.getAttribute(CharTermAttribute.class); System.out.println(token.toString()); ...

lucene • Analysis