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Articles on Trending Technologies
Technical articles with clear explanations and examples
Multiple LIKE Operators with ORDER BY in MySQL?
Following is the syntax implementing multiple LIKE operators with ORDER BY −select *from yourTableName order by ( yourColumnName like '%yourValue1%' ) + ( yourColumnName like '%yourValue2%' ) + . . N desc;Let us create a table −mysql> create table demo2 −> ( −> id int not null auto_increment, −> name varchar(100), −> primary key(id) −> ); Query OK, 0 rows affected (1.53 sec)Insert some records into the table with the help of insert command −mysql> insert into demo2(name) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into demo2(name) values('David'); Query OK, 1 row affected (0.09 ...
Read MoreHow to get number located at 2 places before decimal point MySQL?
In order to get number located at 2 places before decimal point, you can use the concept of div.Let us create a table −mysql> create table demo1 −> ( −> value float −> ); Query OK, 0 rows affected (2.20 sec)Insert some records into the table with the help of insert command −mysql> insert into demo1 values(456.54); Query OK, 1 row affected (0.16 sec) mysql> insert into demo1 values(50.64); Query OK, 1 row affected (0.17 sec) mysql> insert into demo1 values(1000.78); Query OK, 1 row affected (0.13 sec)Display records from the table using select statement −mysql> select *from demo1;This will ...
Read MoreHow to get the list of packages installed in base R?
There is no limitation to installation of packages in R but base R also has some packages associated to it. Hence, there is no need to install or load them in R console every time. We can directly use any of the base R package functions to perform the analysis. If we want to get the list of these package then we can use the code as shown below:Example> installed.packages(priority="base")OutputPackage LibPath Version Priority base "base" "C:/Program Files/R/R-4.0.2/library" "4.0.2" "base" compiler "compiler" "C:/Program Files/R/R-4.0.2/library" "4.0.2" "base" datasets "datasets" "C:/Program Files/R/R-4.0.2/library" "4.0.2" "base" graphics "graphics" "C:/Program Files/R/R-4.0.2/library" "4.0.2" "base" grDevices "grDevices" "C:/Program ...
Read MoreHow to create QR code in R?
A QR code is a barcode which is used to read the information about the object on which it is printed. This helps us to detect the useful information relevant to the object so that we can proceed with the next step depending on the operation. In R, we can create QR code by using qrcode_gen function of qrcode package.Example1Loading qrcode package:> library(qrcode)Creating a QR code for tutorialspoint:> qrcode_gen('www.tutorialspoint.com')Output:Example2> qrcode_gen('www.tutorix.com')Output:Example3> qrcode_gen('www.r-project.org')Output:
Read MoreHow to add a picture to plot in base R?
To add a picture to a plot in base R, we first need to read the picture in the appropriate format and then rasterImage function can be used. The most commonly used format for picture in R is PNG. A picture in PNG format can be added to a plot by supplying the values in the plot where we want to add the picture.ExampleLoading png package:> library(png)Reading png file:> Picture plot(1:10,ty="n")Output:Adding the picture in png file to the above plot:Example> rasterImage(Picture,3,3,7,7)Output:Example> plot(1:10,ty="n") > rasterImage(Picture,5,5,7,7)Output:
Read MoreHow to perform cartesian join for two data.table objects in R?
The cartesian join is the joining of two objects that creates the combination of each value in object with all the values in the other object. For example, if we have a vector x that contains 1, 2, 3 and the other object y contains a, b, c then the cartesian join will be 1a, 2a, 3a, 1b, 2b, 3b, 1c, 2c, and 3c. Check out the below examples to understand how it can be done.Example> library(data.table) > DT1 DT1Output x 1: 1 2: 2 3: 3 4: 4Example> DT2 DT2Output y 1: 25 2: ...
Read MoreHow to create a blank csv file in R?
We can create a blank csv file using a single line code in R and the function that can do this is cat. If we want to have the file blank then NULL value will be passed inside the function and the file name must be used. For example, if we want to create a blank file named as BlankCSV then it can be created by using the below code:> cat(NULL, file="BlankCSV.csv")Output:This is the output from documents folder of the system where all the R files are stored by default(we can change that location if we want to):The output of ...
Read MoreSparse Matrix Multiplication in C++
Suppose we have two matrices A and B, we have to find the result of AB. We may assume that A's column number is equal to B's row number.So, if the input is like [[1, 0, 0], [-1, 0, 3]] [[7, 0, 0], [0, 0, 0], [0, 0, 1]], 100-103700000001then the output will be [[7, 0, 0], [-7, 0, 3]]700-703To solve this, we will follow these steps −r1 := size of A, r2 := size of Bc1 := size of A[0], c2 := size of B[0]Define one 2D array ret of order r1 x c2Define an array sparseA[r1] of pairsfor ...
Read MoreForm validation using Django
In this article, we are going to learn how to validate a form in django. Django comes with build-in validators for forms. We can use them in the tutorial to validate forms.You must familiar with the Django to follow along with this tutorial. If you are not familiar with Django, then this article is not for you.Set up the basic Django project with the following commands.mkdir form_validation cd form_validation python -m venv env (Activate environment based on your OS) pip install django===3.0 django-admin startproject form_validation . (Don't forget dot(.) at the end) python manage.py startapp ...
Read MoreMaximum Sum of Two Non-Overlapping Subarrays in C++
Suppose we have an array A of integers; we have to find the maximum sum of elements in two non−overlapping subarrays. The lengths of these subarrays are L and M.So more precisely we can say that, we have to find the largest V for whichV = (A[i] + A[i+1] + ... + A[i+L-1]) + (A[j] + A[j+1] + ... + A[j+M-1]) and either −0 = 0, decrease i by 1, decrease j by 1, do −rightL[i + 1] := max of temp and x where x is 0 if i + 2 >= n otherwise x = rightL[i + 2]temp ...
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