Tutorial by Examples: f

@echo off prevents the prompt and contents of the batch file from being displayed, so that only the output is visible. The @ makes the output of the echo off command hidden as well.

Ways to create a file with the echo command: ECHO. > example.bat (creates an empty file called "example.bat") ECHO message > example.bat (creates example.bat containing "message") ECHO message >> example.bat (adds "message" to a new line in example.bat)...

In OpenCV, images can be RGB/BGR, HSV, grayscaled, black-white and so on. It is crucial to know the data type before dealing with images. The image data types are mainly CV_8UC3 (Matrix of uchar with 3 channels) and CV_8U (Matrix of uchar with 1 channel), however, the conversion to other types such...

import React from 'react'; class SearchEs6 extends React.Component{ constructor(props) { super(props); this.state = { searchResults: [] }; } showResults(response){ this.setState({ searchResults: response.results ...

Android now supports devices with 512MB of RAM. This documentation is intended to help OEMs optimize and configure Android 4.4 for low-memory devices. Several of these optimizations are generic enough that they can be applied to previous releases as well. Enable Low Ram Device flag We are introduc...

There are two main functions in Redis (HSET and HMSET) for adding fields to a hash key. Both functions are available in redis-py. Using HSET: import redis r = redis.StrictRedis(host='myserver', port=6379, db=0) r.hset('my_key', 'field0', 'value0') Using HMSET: import redis r = redis.St...

Redis provides the LPOP and RPOP commands as a counterpart to the LPUSH and RPUSH commands for fetching data items. If I was working with a list my_list that had several data items in it already, I can get the first item in the list using the LPOP command: LPOP my_list The result of this comman...

The size of a set can be determined using the SCARD command. SCARD will return the cardinality of a set or the number of members in the set. For example, if I had a Redis set my_set stored in the database that looked like (Apple, Orange, Banana), I could get the size using the following code: SCA...

Redis supplies the SISMEMBER command to test if a particular item is already a member of a set. Using the SISMEMBER command I can test and see if apple is already a member of my fruit set. If I construct my fruit set from the previous example, I can check and see if it contains apple using the fol...

The size of a Redis list can be deterimed using the LLEN command. If I have a four element list stored at the key my_list, I can get the size using: LLEN my_list which will return 4. If a user specifies a key that doesn't exist to LLEN, it will return a zero, but if a key is used that points t...

Redis provides seven different operations for working with scripts: Eval operations (EVAL, EVALSHA) SCRIPT operations (DEBUG, EXISTS, FLUSH, KILL, LOAD) The EVAL command evaluates a script provided as a string argument to the server. Scripts can access the specified Redis keys named as argum...

/** * Resizes an image using a Graphics2D object backed by a BufferedImage. * @param srcImg - source image to scale * @param w - desired width * @param h - desired height * @return - the new resized image */ private BufferedImage getScaledImage(Image srcImg, int w, int h){ //Cre...

Be aware that the WebBrowser control is not sympathetic to your XAML definition, and renders itself over the top of other things. For example, if you put it inside a BusyIndicator that has been marked as being busy, it will still render itself over the top of that control. The solution is to bind th...

g + geom_bar(aes(x = cut, fill = color), position = "fill") + guides(fill = guide_legend(title = NULL))

g + geom_bar(mapping = aes(x = cut, fill = clarity), position = "dodge") + theme(axis.text = element_text(colour = "red", size = 12))

g + geom_histogram(aes(price, fill = cut), binwidth = 500) + labs(x = "Price", y = "Number of diamonds", title = "Distribution of prices \n across Cuts") + theme(plot.title = element_text(colour = "red", face = "italic"), ...

We show a plot similar to the showed at Linear regression on the mtcars dataset. First with defaults and the with some customization of the parameters. #help("mtcars") fit <- lm(mpg ~ wt, data = mtcars) bs <- round(coef(fit), 3) lmlab <- paste0("mpg = ", bs[1], ...

How to ... 1 - use twig extension class that extends use \Twig_Extension class dobToAge extends \Twig_Extension { 2 - Add the appropriate filter by overriding getFilters() method public function getFilters() { return array( 'age' => new \Twig_Filter_Method($this, '...

If you need to select between several options, enabling just one via enable_if<> can be quite cumbersome, since several conditions needs to be negated too. The ordering between overloads can instead be selected using inheritance, i.e. tag dispatch. Instead of testing for the thing that ne...

This is the typical approach for novice developers building SQL action queries. They are vulnerable to the Bobby Tables type SQL Injection attacks. Dim strSQL As String strSQL = "INSERT INTO Employees chrFirstName, chrLastName, chrPhone " _ & "VALUES ('" & M...