Tutorial by Examples: d

This example shows how to create a table, insert data, and select from the database using the SQLAlchemy ORM. For information re: SQLAlchemy Core, see here. First things first, we need to connect to our database, which is identical to how we would connect using SQLAlchemy Core (Core). from sqlalch...

@media print { p { page-break-inside: avoid; } h1 { page-break-before: always; } h2 { page-break-after: avoid; } } This code does 3 things: it prevents a page break inside any p tags, meaning a paragraph will never be broken in two pages, if possible. it for...

Make sure your tomcat configurations file, server.xml has this line: <Connector port="8443" protocol="org.apache.coyote.http11.Http11Protocol" maxHttpHeaderSize="8192" SSLEnabled="true" maxThreads="150" minSpareThrea...

PHP 5.5 introduces Generators and the yield keyword, which allows us to write asynchronous code that looks more like synchronous code. The yield expression is responsible for giving control back to the calling code and providing a point of resumption at that place. One can send a value along the yi...

A common refrain in R goes along these lines: You should not have a bunch of related tables with names like DT1, DT2, ..., DT11. Iteratively reading and assigning to objects by name is messy. The solution is a list of tables of data! Such a list looks like set.seed(1) DT_list = lapply(setNam...

Using .NET's rich reflection APIs, you can gain access to an assembly's metadata. For example, you can get this assembly's title attribute with the following code using System.Linq; using System.Reflection; ... Assembly assembly = typeof(this).Assembly; var titleAttribute = assembly.GetCust...

Iterators produce enumerators. In C#, enumerators are produced by defining methods, properties or indexers that contain yield statements. Most methods will return control to their caller through normal return statements, which disposes all state local to that method. In contrast, methods that use y...

Vlookup finds some value in the leftmost column of a range and returns a value some number of columns to the right and in the same row. Let's say you want to find the surname of Employee ID 2 from this table: =VLOOKUP(2,$A$2:$C$4,3,0) The value you're retrieving data for is 2 The table you...

Your code in source control has version numbers either by default (SVN ids or Git SHA1 hashes) or explicitly (Git tags). Rather than manually updating versions in AssemblyInfo.cs you can use a build time process to write the version from your source control system into your AssemblyInfo.cs files and...

It's good practice to complete your AssemblyInfo's default fields. The information may be picked up by installers and will then appear when using Programs and Features (Windows 10) to uninstall or change a program. The minimum should be: AssemblyTitle - usually the namespace, i.e. MyCompany.MySo...

A higher-order function is one that takes another function as an argument or returns a function (or both). This is commonly done with lambdas, for example when passing a predicate to a LINQ Where clause: var results = data.Where(p => p.Items == 0); The Where() clause could receive many diffe...

This example shows how a MongoDB collection can be displayed in a React component. The collection is continuously synchronized between server and client, and the page instantly updates as database contents change. To connect React components and Meteor collections, you'll need the react-meteor-data...

function onOpen() { // Add a custom menu to run the script var ss = SpreadsheetApp.getActiveSpreadsheet(); var searchMenuEntries = [ {name: "Run", functionName: "search"}]; ss.addMenu("Get Files", searchMenuEntries); } function getFiles() { // Get...

PMF FOR THE BINOMIAL DISTRIBUTION Suppose that a fair die is rolled 10 times. What is the probability of throwing exactly two sixes? You can answer the question using the dbinom function: > dbinom(2, 10, 1/6) [1] 0.29071 PMF FOR THE POISSON DISTRIBUTION The number of sandwhich ordered in ...

General Using the package RMySQL we can easily query MySQL as well as MariaDB databases and store the result in an R dataframe: library(RMySQL) mydb <- dbConnect(MySQL(), user='user', password='password', dbname='dbname',host='127.0.0.1') queryString <- "SELECT * FROM table1 t1 JO...

Knitr is an R package that allows us to intermingle R code with LaTeX code. One way to achieve this is external code chunks. External code chunks allow us to develop/test R Scripts in an R development environment and then include the results in a report. It is a powerful organizational technique....

FunctionWidgetactionButtonAction ButtoncheckboxGroupInputA group of check boxescheckboxInputA single check boxdateInputA calendar to aid date selectiondateRangeInputA pair of calendars for selecting a date rangefileInputA file upload control wizardhelpTextHelp text that can be added to an input form...

We try to extract imdb top chart movies and ratings R> library(RCurl) R> library(XML) R> url <- "http://www.imdb.com/chart/top" R> top <- getURL(url) R> parsed_top <- htmlParse(top, encoding = "UTF-8") R> top_table <- readHTMLTable(parsed_top)[...

The SilverStripe Grid Field Extensions Module has some very nice features to enhance the basic GridField... GridFieldAddExistingSearchButton - a more advanced search form for adding items GridFieldAddNewInlineButton - builds on GridFieldEditableColumns to allow inline creation of records. GridF...

The module Better Buttons for GridField adds new form actions and buttons to the GridField detail form. Save and add another: Create a record, and go right to adding another one, without having to click the back button, and then add again Save and close: Save the record and go back to list view ...