Tutorial by Topics: o

$this->load->library('library_name'); $this->library_name->function_name(); $this->load->library('cart'); # for helper $this->load->helper('helperName'); $this->cart->insert($Array);

Aggregations are methods allowing the execution of operations on (individual and/or groups of) rows of objects derived from a Model.

The official vignette, "Reference semantics", is the best introduction to this topic. A reminder: DT[where, select|update|do, by] syntax is used to work with columns of a data.table. The "where" part is the i argument The "select|update|do" part is the j argument...

@AnAnnotation def someMethod = {...} @AnAnnotation class someClass {...} @AnnotatioWithArgs(annotation_args) def someMethod = {...} ParameterDetails@Indicates that the token following is an annotation.SomeAnnotationThe name of the annotationconstructor_args(optional) The arguments passed t...

A reminder: DT[where, select|update|do, by] syntax is used to work with columns of a data.table. The "where" part is the i argument The "select|update|do" part is the j argument These two arguments are usually passed by position instead of by name.

A reminder: DT[where, select|update|do, by] syntax is used to work with columns of a data.table. The "where" part is the i argument The "select|update|do" part is the j argument These two arguments are usually passed by position instead of by name.

The special symbol .SD is available in j of DT[i,j,by], capturing the Subset of Data for each by group surviving the filter, i. .SDcols is a helper. Type ?`special-symbols` for the official docs. A reminder: DT[where, select|update|do, by] syntax is used to work with columns of a data.table. T...

The sqlite3 command-line shell implements an additional set of commands (which are not available in programs that use the SQLite library). Official documentation: Special commands to sqlite3

Folding causes multiple lines of text to be collapsed and displayed as a single line. It is useful for hiding portions of a document considered unimportant for the current task. Folding is purely a visual change to the document: the folded lines are still present, unchanged. A fold is persistent....

public static GameObject Find(string name); public static GameObject FindGameObjectWithTag(string tag); public static GameObject[] FindGameObjectsWithTag(string tag); public static Object FindObjectOfType(Type type); public static Object[] FindObjectsOfType(Type type); Which method to...

New versions of Ubuntu are released by Canonical every 6 months. Every two years, the release is a Long Term Support version. Support lifespan Normal release - supported for 9 months Long Term Support (LTS) release    • LTS releases for Ubuntu Desktop, Ubuntu Server, Ubuntu Core, and Ubuntu ...

$ shopt -u option # Deactivate Bash's built-in 'option' $ shopt -s option # Activate Bash's built-in 'option' Character Classes Valid character classes for the [] glob are defined by the POSIX standard: alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdig...

Entity Framework (EF) Core is a lightweight and extensible version of the popular Entity Framework data access technology. EF Core is an object-relational mapper (O/RM) that enables .NET developers to work with a database using .NET objects. It eliminates the need for most of the data-access code...

There are many excellent reference and example sources on the Web. Some examples and explanations are created here as a collection point for quick answers. More detailed illustrations may be linked to external content (instead of copying existing original material).