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The array_filter() or PREG_SPLIT_NO_EMPTY option on preg_split() can be used to remove empty values from a string when it is exploded −Example Live Demo
The fopen can’t be used to create directories. This is because fopen function doesn't create or open folders, it only works with files.Before using the fopen function, one should check with is_dir first if it exists, if not create it using the mkdir function −$filename = '/path/to /file.txt'; $dirname = dirname($filename); if (!is_dir($dirname)) { mkdir($dirname, 0755, true); }The above code creates a path to the file named ‘filename’. The directory of the ‘filename’ is obtained using the ‘dirname’ function. Next, this directory is checked for the existence using the ‘is_dir’ function. If the directory already exists, no operation takes ... Read More
The below code can be used to import CSV file in PHP −The file will display the contents of the csv file are displayed on the screen.In the above code, beginning from row 1 (since row 0 would usually contain headers/column names), the csv file is opened in read mode and the fgetcsv function is called to read in 1000 rows of data present in the csv file.The number of columns in every row is displayed along with the contents of it.
To check if a folder or a file is in use, the function is_dir() or is_file() can be used.The scandir function is an inbuilt function that returns an array of files and directories of a specific directory. It lists the files and directories present inside the path specified by the user.For example$scan = scandir('myFolder'); foreach($scan as $file) { if (!is_dir("myFolder/$file")) { echo $file.''; } }OutputList of files and directories inside the path specified (if any)The directory ‘myFolder’ is scanned using the ‘scandir’ function and the files and directories inside it are listed out. The ‘foreach’ ... Read More
When the backslash \ does not escape the terminating quote of the string or even create a valid escape sequence (in double quoted strings), then the below code can be used to produce one backslash −Example Live Demo$string = 'abc\def'; print($string);OutputThis will produce the following output −abc\defExample Live Demo$string = "abc\def"; print($string);OutputThis will produce the following output −abc\def
JShell has introduced in Java 9 and is a command-line tool that allows us to enter simple statements, expressions, methods, and classes without a main () method.When we can enter code in JShell, the code has assigned a unique ID. This ID starts at 1 and has incremented for each command entered in JShell. The same can be true for libraries loaded at startup. For each of these imports, a unique ID has been assigned. It starts with $1 and is incremented for each code loaded ($2, $3 and etc). There is an internal command to list all code loaded, and ... Read More
In OpenCV Mat class represents a matrix object which is used to store images. You can also declare a Mat object manually −Load the OpenCV native library − While writing Java code using OpenCV library, the first step you need to do is to load the native library of OpenCV using the loadLibrary().Instantiate the Mat class − Instantiate the Mat class using any of the functions mentioned in this chapter earlier.Fill the matrix using the methods − You can retrieve particular rows/columns of a matrix by passing index values to the methods row()/col().you can set values to these using any of ... Read More
In OpenCV, images are stored in Using Mat object. It is nothing but an n-dimensional array and is used to store image data of grayscale or color images, voxel volumes, vector fields, point clouds, tensors, histograms, etc.If you try to read an image using the OpenCV library it will be read to a Mat object.Mat matrix = Imgcodecs.imread(filePath);You can instantiate this class manually using one of the following constructors −Mat() − A no-arg constructor, used to create an empty matrix and pass this to other OpenCV methods.Mat(int rows, int cols, int type) − This constructor accepts three parameters of integer ... Read More
The applyColorMap() method of the Imgproc class applies specified color map to the given image. This method accepts three parameters −Two Mat objects representing the source and destination images.An integer variable representing the type of the color map to be applied.You can pass any of the following as color map value to this method.COLORMAP_AUTUMN, COLORMAP_BONE, COLORMAP_COOL, COLORMAP_HOT, COLORMAP_HSV, COLORMAP_JET, COLORMAP_OCEAN , COLORMAP_PARULA, COLORMAP_PINK, COLORMAP_RAINBOW, COLORMAP_SPRING, COLORMAP_SUMMER, COLORMAP_WINTER.Exampleimport org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class CustomColorMaps { public static void main(String args[]) { // Loading the OpenCV core library System.loadLibrary(Core.NATIVE_LIBRARY_NAME); ... Read More
The equalizeHist() method of the Imgproc class accepts a greyscale image and equalizes its histogram, which will, in turn, normalizes the brightness and increases the contrast of the given image. This method accepts two parameters −A Mat object representing the source image (greyscale).A Mat object to save the result.ExampleFollowing Java program reads a colored image as greyscale, saves it, normalizes the brightness and increases the contrast of the given image and saves it.import org.opencv.core.Core; import org.opencv.core.Mat; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class HstExample { public static void main(String args[]) { //Loading the OpenCV core ... Read More