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undef # False '' # Defined, False 0 # Defined, Has Length, False '0' # Defined, Has Length, False Perl does not have a boolean data type, nor does it have any true and false keywords like many other languages. However, every scalar value will evaluate to true or false when evalu...

while (boolean_expression) { block_expression } do { block_expression } while (boolean_expression) ParameterDetailsboolean_expressionAny expression that will evaluate to true or false.block_expressionAny expression or set of expressions that will be evaluated if the boolean_expres...

Pipe operators, available in magrittr, dplyr, and other R packages, process a data-object using a sequence of operations by passing the result of one step as input for the next step using infix-operators rather than the more typical R method of nested function calls. Note that the intended aim of p...

QML is an acronym that stands for Qt Meta-object Language. It is a declarative programming language that is part of the Qt framework. QML's main purpose is fast and easy creation of user interfaces for desktop, mobile and embedded systems. QML allows seamless integration of JavaScript, either dire...

Docker is an open-source project that automates the deployment of applications inside software containers. These application containers are similar to lightweight virtual machines, as they can be run in isolation to each other and the running host. Docker requires features present in recent linux...

Lua is minimalistic, lightweight and embeddable scripting language. It's being designed, implemented, and maintained by a team at PUC-Rio, the Pontifical Catholic University of Rio de Janeiro in Brazil. The mailing list is open to get involved. Common use-cases for Lua includes scripting video...

selector match partialFunction selector match {list of case alternatives) // This is most common form of the above ParameterDetailsselectorThe expression whose value is being pattern-matched.alternativesa list of case-delimited alternatives.

svn copy [BRANCH-FROM-URL] [BRANCH-TO-URL] -m <COMMIT-LOG-MESSAGE> svn copy [^/PATH-TO-BRANCH-FROM] [^/PATH-TO-BRANCH-TO] -m <COMMIT-LOG-MESSAGE> As you might have noticed, we use svn copy command to create branches, tags and shelves (we'll skip mentioning tags and shel...

for {clauses} body for {clauses} yield body for (clauses) body for (clauses) yield body ParameterDetailsforRequired keyword to use a for loop/comprehensionclausesThe iteration and filters over which the for works.yieldUse this if you want to create or 'yield' a collection. Using yield wil...

ASDF - Another System Definition Facility ASDF is a tool for specifying how systems of Common Lisp software are made up of components (sub-systems and files), and how to operate on these components in the right order so that they can be compiled, loaded, tested, etc.

lua_State *L = lua_open(); // Create a new VM state; Lua 5.0 lua_State *L = luaL_newstate(); // Create a new VM state; Lua 5.1+ int luaL_dofile(lua_State *L, const char *filename); // Run a lua script with the given filename using the specified lua_State void luaL_openlibs(lua_State *L); // Lo...

A cherry-pick takes the patch that was introduced in a commit and tries to reapply it on the branch you’re currently on. Source: Git SCM Book git cherry-pick [--edit] [-n] [-m parent-number] [-s] [-x] [--ff] [-S[key-id]] commit... git cherry-pick --continue git cherry-pick --quit git cher...

var x int // declare variable x with type int var s string // declare variable s with type string x = 4 // define x value s = "foo" // define s value y := 5 // declare and define y inferring its type to int f := 4.5 // declare and define f inferring its type to float64 b := &quo...

IBM Watson Speech to Text offers a variety of options for transcribing audio in various languages and formats: WebSockets – establish a persistent connection over the WebSocket protocol for continuous transcription Sessionless – transcribe audio without the overhead of establishing and m...

ipairs(numeric_table) -- Lua table with numeric indices iterator pairs(input_table) -- generic Lua table iterator key, value = next(input_table, input_key) -- Lua table value selector table.insert(input_table, [position], value) -- insert specified value into the input table removed_value = ta...

A database snapshot is a read-only, static view of a SQL Server database which is transactionally consistent with the source database as of the moment of the snapshot's creation. A database snapshot always resides on the same server instance as its source database. As the source database is updat...