Tutorial by Examples: s

Imagine that we have a class Math.php with logic of calculating of fiobanacci and factorial numbers. Something like this: <?php class Math { public function fibonacci($n) { if (is_int($n) && $n > 0) { $elements = array(); $elements[1] = 1; ...

Once the type handlers are registered, everything should work automatically, and you should be able to use these types as either parameters or return values: string redmond = "POINT (122.1215 47.6740)"; DbGeography point = DbGeography.PointFromText(redmond, DbGeography.DefaultCoordi...

When using Access you can retrieve data using queries. These queries are built using Structured Query Language (SQL). Understanding SQL is important because it can help build better, more useful queries. When creating queries in Access, you can switch to "SQL View". An example of a "...

When you wish to combine the results of multiple tables or queries with similar fields together into a single resulting data set without performing any relational joins (i.e. you want to list one dataset immediately after the other), you will use a UNION query. However, it is notable that these quer...

The most important object in the Browser Object Model is the window object. It helps in accessing information about the browser and its components. To access these features, it has various methods and properties. MethodDescriptionwindow.alert()Creates dialog box with message and an OK buttonwindow....

The http_build_query() will create a query string from an array or object. These strings can be appended to a URL to create a GET request, or used in a POST request with, for example, cURL. $parameters = array( 'parameter1' => 'foo', 'parameter2' => 'bar', ); $queryString = http_b...

Basic usage If the value of the href-attribute begins with mailto: it will try to open an email client on click: <a href="mailto:[email protected]">Send email</a> This will put the email address [email protected] as the recipient for the newly created email. Cc and ...

When INSERTing, you can use OUTPUT INSERTED.ColumnName to get values from the newly inserted row, for example the newly generated Id - useful if you have an IDENTITY column or any sort of default or calculated value. When programatically calling this (e.g., from ADO.net) you would treat it as a nor...

<PropertyGroup> <!-- Definition of a Property named "TestCondition". A PropertyGroup may also be placed inside a Target. --> <TestCondition>True</TestCondition> </PropertyGroup> <!-- This Target will run after the "Clean" Target, su...

For efficiency, data.table offers a way of altering a data.frame or list to make a data.table in-place: # example data.frame DF = data.frame(x = letters[1:5], y = 1:5, z = (1:5) > 3) # modification setDT(DF) Note that we do not <- assign the result, since the object DF has been modifi...

# example data DT = data.table(Titanic) Suppose we only want to see second class: DT[ Class == "2nd" ] # Class Sex Age Survived N # 1: 2nd Male Child No 0 # 2: 2nd Female Child No 0 # 3: 2nd Male Adult No 154 # 4: 2nd Female Adult ...

# example data DT = data.table(Titanic) Suppose we want to see each class only if a majority survived: DT[, if (sum(N[Survived=="Yes"]) > sum(N[Survived=="No"]) ) .SD, by=Class] # Class Sex Age Survived N # 1: 1st Male Child No 0 # 2: 1st Fema...

Match (node_name:node_type {}), (node_name_two:node_type_two {}) CREATE (node_name)-[::edge_name{}]->(node_name_two)

The DISTINCT clause after SELECT eliminates duplicate rows from the result set. CREATE TABLE `car` ( `car_id` INT UNSIGNED NOT NULL PRIMARY KEY, `name` VARCHAR(20), `price` DECIMAL(8,2) ); INSERT INTO CAR (`car_id`, `name`, `price`) VALUES (1, 'Audi A1', '20000'); INSERT INTO CA...

A quick note before actually installing RabbitMQ: Ubuntu 14.04's Erlang packages have issues if you are using SSL with RabbitMQ, so you'll need to install a newer version than what the Ubuntu package maintainers provide, so use the binaries at https://www.erlang-solutions.com/resources/download.html...

Monotonic predicates can be debugged by applying declarative reasoning. In pure Prolog, a programming mistake can lead to one or all of the following phenomena: the predicate incorrectly succeeds in a case where it should fail the predicate incorrectly fails in a case where it should succeed t...

Examples of monotonic predicates are: unification with (=)/2 or unify_with_occurs_check/2 dif/2, expressing disequality of terms CLP(FD) constraints like (#=)/2 and (#>)/2, using a monotonic execution mode. Prolog predicates that only use monotonic goals are themselves monotonic. Monoton...

Here are examples of predicates that are not monotonic: meta-logical predicates like var/1, integer/1 etc. term comparison predicates like (@<)/2 and (@>=)/2 predicates that use !/0, (\+)/1 and other constructs that break monotonicity all-solutions predicates like findall/3 and setof/3. ...

Here are examples of how to use monotonic predicates instead of impure, non-monotonic constructs in your programs: dif/2 is meant to be used instead of non-monotonic constructs like (\=)/2 arithmetic constraints (CLP(FD), CLP(Q) and others) are meant to be used instead of moded arithmetic predi...

Sometimes what you have is a list, but the command you want to pass the items in the list to demands to get each item as a separate argument. For instance: the winfo children command returns a list of windows, but the destroy command will only take a sequence of window name arguments. set alpha [wi...