Tutorial by Topics: o

Results of a SELECT query can be grouped by one or more columns using the GROUP BY statement: all results with the same value in the grouped columns are aggregated together. This generates a table of partial results, instead of one result. GROUP BY can be used in conjunction with aggregation functio...

X-macros are a preprocessor-based technique for minimizing repetitious code and maintaining data / code correspondences. Multiple distinct macro expansions based on a common set of data are supported by representing the whole group of expansions via a single master macro, with that macro's replacem...

Reflection is commonly used by programs which require the ability to examine or modify the runtime behavior of applications running in the JVM. Java Reflection API is used for that purpose where it makes it possible to inspect classes, interfaces, fields and methods at runtime, without knowing their...

$(function() { $( "#selecter" ).accordion(); }); $(function() { $( "#selecter" ).accordion({ active: 2 }); }); $(function() { $( "#selecter" ).accordion({ animate: 200 }); }); $(function() { $( "#selecter" ).accordion({ collapsible: true }); ...

Python makes regular expressions available through the re module. Regular expressions are combinations of characters that are interpreted as rules for matching substrings. For instance, the expression 'amount\D+\d+' will match any string composed by the word amount plus an integral number, separate...

__getFunctions() // Returns array of functions for service (WSDL mode only) __getTypes() // Returns array of types for service (WSDL mode only) __getLastRequest() // Returns XML from last request (Requires trace option) __getLastRequestHeaders() // Returns headers from last request (Requires t...

InputBox(prompt[, title][, default][, xpos][, ypos][, helpfile, context]) ArgumentDetailpromptText to display above the input field (usually an instruction as to what is required form the user).titleCaption displayed in the titlebar of the input box.defaultA placeholder for the text field, u...

Local notifications allow your app to notify the user about content which does not require the use of a server. Unlike remote notifications which are triggered from a server, local notifications are scheduled and triggered within an app. Notifications in general are targeted to increase user intera...

Positive lookahead: (?=pattern) Negative lookahead: (?!pattern) Positive lookbehind: (?<=pattern) Negative lookbehind: (?<!pattern) Not supported by all regex engines. Additionally, many regex engines limit the patterns inside lookbehinds to fixed-length strings. For example the p...

Some languages require you to define ahead of time what kind of variable you're declaring. JavaScript doesn't do that; it will try to figure that out on its own. Sometimes this can create unexpected behavior. If we use the following HTML <span id="freezing-point">0</span> ...

color: #rgb color: #rrggbb color: rgb[a](<red>, <green>, <blue>[, <alpha>]) color: hsl[a](<hue>, <saturation%>, <lightness%>[, <alpha>]) color: colorkeyword /* green, blue, yellow, orange, red, ..etc */

box-sizing: parameter; ParameterDetailcontent-boxWidth and height of the element only includes content area.padding-boxWidth and height of the element includes content and padding.border-boxWidth and height of the element includes content, padding and border.initialSets the box model to its ...

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...

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...