Tutorial by Examples: e

-> Note: make sure you set up HStoreField first before going on with this example. (above) No parameters are required for initializing a HStoreField. from django.contrib.postgres.fields import HStoreField from django.db import models class Catalog(models.model): name = models.C...

Pass a native python dictionary mapping strings to strings to create(). Catalog.objects.create(name='Library of Congress', titles_to_authors={ 'Using HStoreField with Django': 'CrazyPython and la communidad', 'Flabbergeists and thingamajigs': 'La Artista Fooista', 'Pro Git': 'Scott C...

Catalog.objects.filter(titles__Pro_Git='Scott Chacon and Ben Straub')

The @while directive will loop over a block of code until the condition specified becomes false. In the following example, this loop will run until $font-size <= 18 while incrementing the value for $font-size by 2. $font-size: 12; @while $font-size <= 18 { .font-size-#{$font-size} { ...

You often find yourself in a situation where you need to find a variables corresponding value, and collections got you covered. In the example below we got three different locales in an array with a corresponding calling code assigned. We want to be able to provide a locale and in return get the as...

# Fetch and install package to setup access to the official APT repository wget https://packages.erlang-solutions.com/erlang-solutions_1.0_all.deb sudo dpkg -i erlang-solutions_1.0_all.deb # Update package index sudo apt-get update # Install Erlang and Elixir sudo apt-get install esl-erlan...

5 With ES5+, the Object.create function can be used to create an Object with any other Object as it's prototype. const anyObj = { hello() { console.log(`this.foo is ${this.foo}`); }, }; let objWithProto = Object.create(anyObj); objWithProto.foo = 'bar'; objWithProto.hell...

Run command below to install nginx. sudo apt-get install nginx By default, Nginx automatically starts when it is installed. You can access the default Nginx landing page to confirm that the software is running properly by visiting your server's domain name or public IP address in your web browse...

Dim array2D(,) As Integer = {{1, 2, 3}, {4, 5, 6}} ' array2D(0, 0) is 1 ; array2D(0, 1) is 2 ; array2D(1, 0) is 4 Dim array3D(,,) As Integer = {{{1, 2, 3}, {4, 5, 6}}, {{7, 8, 9}, {10, 11, 12}}} ' array3D(0, 0, 0) is 1 ; array3D(0, 0, 1) is 2 ' array3D(0, 1, 0) is 4 ; array3D(1, 0, 0) is 7 ...

Note the parenthesis to distinguish between a jagged array and a multidimensional array SubArrays can be of different length Dim jaggedArray()() As Integer = { ({1, 2, 3}), ({4, 5, 6}), ({7}) } ' jaggedArray(0) is {1, 2, 3} and so jaggedArray(0)(0) is 1 ' jaggedArray(1) is {4, 5, 6} and so jagge...

Here is a program that calls malloc but not free: #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { char *s; s = malloc(26); // the culprint return 0; } With no extra arguments, valgrind will not look for this error. But if we turn on...

wikipedia definition: Command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an action or trigger an event at a later time UML diagram from dofactory: Basic components and workflow: Command declares an interface for abst...

Quantifiers allows to specify count of repeated strings. Zero or one: /a?/ Zero or many: /a*/ One or many: /a+/ Exact number: /a{2,4}/ # Two, three or four /a{2,}/ # Two or more /a{,4}/ # Less than four (including zero) By default, quantifiers are greedy, whi...

Describes ranges of symbols You can enumerate symbols explicitly /[abc]/ # 'a' or 'b' or 'c' Or use ranges /[a-z]/ # from 'a' to 'z' It is possible to combine ranges and single symbols /[a-cz]/ # 'a' or 'b' or 'c' or 'z' Leading dash (-) is treated as charachter /[-a-c]/ # '-' or 'a' o...

Unions are a specialized struct within which all members occupy overlapping memory. union U { int a; short b; float c; }; U u; //Address of a and b will be equal (void*)&u.a == (void*)&u.b; (void*)&u.a == (void*)&u.c; //Assigning to any union member changes ...

Unions are useful for minimizing memory usage for exclusive data, such as when implementing mixed data types. struct AnyType { enum { IS_INT, IS_FLOAT } type; union Data { int as_int; float as_float; } value; AnyType(int i) : type...

You can test if a string matches several regular expressions using a switch statement. Example case "Ruby is #1!" when /\APython/ puts "Boooo." when /\ARuby/ puts "You are right." else puts "Sorry, I didn't understand that." end This w...

Pointer initialization is a good way to avoid wild pointers. The initialization is simple and is no different from initialization of a variable. #include <stddef.h> int main() { int *p1 = NULL; char *p2 = NULL; float *p3 = NULL; /* NULL is a macro defined in st...

All versions of SharePoint are based around Sites (SPSite (SSOM) or Site (CSOM)) and Webs (SPWeb(SSOM) or Web(CSOM)). A site is not rendered in the UI although it does contain metadata and features that are applied to its children. A web is the basic building block that renders a UI to the user acce...

ClientContext clientContext = new ClientContext(siteUrl); Web oWebsite = clientContext.Web; clientContext.Load(oWebsite); clientContext.ExecuteQuery(); Console.WriteLine("Title: {0} Description: {1}", oWebsite.Title, oWebsite.Description);