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Responses can be written to a http.ResponseWriter using templates in Go. This proves as a handy tool if you wish to create dynamic pages. (To learn how Templates work in Go, please visit the Go Templates Documentation page.) Continuing with a simple example to utilise the html/template to respond ...

In order to install PostgreSQL on OSX, you need to know which versions are currently supported. Use this command to see what versions you have available. sudo port list | grep "^postgresql[[:digit:]]\{2\}[[:space:]]" You should get a list that looks something like the following: post...

Ruby Standard Library has a Singleton module which implements the Singleton pattern. The first step in creating a Singleton class is to require and include the Singleton module in a class: require 'singleton' class Logger include Singleton end If you try to instantiate this class as you n...

When working with regular expressions one modifier for PCRE is g for global match. In R matching and replacement functions have two version: first match and global match: sub(pattern,replacement,text) will replace the first occurrence of pattern by replacement in text gsub(pattern,replace...

class Person { public string FirstName { get; set; } public string LastName { get; set; } } class Pet { public string Name { get; set; } public Person Owner { get; set; } } public static void Main(string[] args) { var magnus = new Person { FirstName = "Magnus...

DynamoDB is a fully managed service provided by AWS. It does not need to be installed or configured. AWS is responsible for all administrative burdens of operating, scalling and backup/restore of the distributed database.

dc is one of the oldest language on Unix. It is using the reverse polish notation, which means that you are first stacking numbers, then operations. For example 1+1 is written as 1 1+. To print an element from the top of the stack use command p echo '2 3 + p' | dc 5 or dc <<< '2 3...

It's often useful to combine multiple plot types in one graph (for example a Barplot next to a Scatterplot.) R makes this easy with the help of the functions par() and layout(). par() par uses the arguments mfrow or mfcol to create a matrix of nrows and ncols c(nrows, ncols) which will serve as a ...

All DATEs have a time component; however, it is customary to store dates which do not need to include time information with the hours/minutes/seconds set to zero (i.e. midnight). Use an ANSI DATE literal (using ISO 8601 Date format): SELECT DATE '2000-01-01' FROM DUAL; Convert it from a string ...

Convert it from a string literal using TO_DATE(): SELECT TO_DATE( '2000-01-01 12:00:00', 'YYYY-MM-DD HH24:MI:SS' ) FROM DUAL; Or use a TIMESTAMP literal: CREATE TABLE date_table( date_value DATE ); INSERT INTO date_table ( date_value ) VALUES ( TIMESTAMP '2000-01-01 12:00:00' ); Oracl...

Use TO_CHAR( date [, format_model [, nls_params]] ): (Note: if a format model is not provided then the NLS_DATE_FORMAT session parameter will be used as the default format model; this can be different for every session so should not be relied on. It is good practice to always specify the format mod...

When Oracle implicitly converts from a DATE to a string or vice-versa (or when TO_CHAR() or TO_DATE() are explicitly called without a format model) the NLS_DATE_FORMAT session parameter will be used as the format model in the conversion. If the literal does not match the format model then an excepti...

When SQL/Plus or SQL Developer display dates they will perform an implicit conversion to a string using the default date format model (see the Setting the Default Date Format Model example). You can change how a date is displayed by changing the NLS_DATE_FORMAT parameter.

The RewriteEngine module within Apache is used to dynamically rewrite URLs and paths depending on various expressions provided: <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d ...

When it comes to geographic data, R shows to be a powerful tool for data handling, analysis and visualisation. Often, spatial data is avaliable as an XY coordinate data set in tabular form. This example will show how to create a spatial data set from an XY data set. The packages rgdal and sp provi...

rgdal ESRI shape files can easily be imported into R by using the function readOGR() from the rgdal package. library(rgdal) shp <- readORG(dsn = "/path/to/your/file", layer = "filename") It is important to know, that the dsn must not end with / and the layer does not all...

Currying is the transformation of a function of n arity or arguments into a sequence of n functions taking only one argument. Use cases: When the values of some arguments are available before others, you can use currying to decompose a function into a series of functions that complete the work in s...

macro(set_my_variable _INPUT) if("${_INPUT}" STREQUAL "Foo") set(my_output_variable "foo") else() set(my_output_variable "bar") endif() endmacro(set_my_variable) Use the macro: set_my_variable("Foo") message(STATUS ${my_outpu...

The difference between size and count is: size counts NaN values, count does not. df = pd.DataFrame( {"Name":["Alice", "Bob", "Mallory", "Mallory", "Bob" , "Mallory"], "City":["Seattle", &q...

A method defined in an interface is by default public abstract. When an abstract class implements an interface, any methods which are defined in the interface do not have to be implemented by the abstract class. This is because a class that is declared abstract can contain abstract method declaratio...