Found 26504 Articles for Server Side Programming

What is OpenCV?

Ginni
Updated on 10-Mar-2021 07:35:56

724 Views

OpenCV stands for open-source computer vision. It was generated to support a common infrastructure for computer vision operations and use system behaviour in financial products. It generally targets image processing, faces recognition, video capture, searching, and object disclosure.OpenCV is created to implement various operations including recognising and detecting faces, analysing human tasks in videos, identifying objects, recording camera movements, tracking moving objects, and combining images to create a high-resolution image for the accurate scene. Let's see the topic defining the term "Computer Vision."Computer VisionComputer vision is a flexible scientific area that manages to regenerate, preventing, and learn a 3D image from ... Read More

What do you mean by static memory allocation in C programming?

Bhanu Priya
Updated on 09-Mar-2021 08:33:58

3K+ Views

Memory can be allocated in the following two ways −Static Memory AllocationStatic variable defines in one block of allocated space, of a fixed size. Once it is allocated, it can never be freed.Memory is allocated for the declared variable in the program.The address can be obtained by using ‘&’ operator and can be assigned to a pointer.The memory is allocated during compile time.It uses stack for maintaining the static allocation of memory.In this allocation, once the memory is allocated, the memory size cannot change.It is less efficient.The final size of a variable is decided before running the program, it will ... Read More

How to extract only first sub-element from a list in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 14:15:37

13K+ Views

To extract only first element from a list, we can use sapply function and access the first element with double square brackets. For example, if we have a list called LIST that contains 5 elements each containing 20 elements then the first sub-element can be extracted by using the command sapply(LIST,"[[",1).Example1Consider the below data frame − Live DemoList1

How to find the monthly average from different date data in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 14:15:10

2K+ Views

To find the monthly average from different date data, we first need to extract the months and year from date column and then find the average using aggregate function. For example, if we have a data frame called df which has three columns say x, month, and year then the monthly average can be found by using the command −aggregate(x~Month+Year,df,mean)Example1Consider the below data frame − Live DemoDate1

How to change the code "Yes" to 1 in an R data frame column?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 14:07:30

15K+ Views

To change the code “Yes” to 1, we can use ifelse function and set the Yes to 1 and others to 0. For example, if we have a data frame called df that contains a character column x which has Yes and No values then we can convert those values to 1 and 0 using the command ifelse(df$x=="Yes",1,0).Example1Consider the below data frame − Live DemoAgree

How to find the count of a particular character in a string vector in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 14:02:00

173 Views

To find the count of a particular character in a string vector we can use nchar function along with gsub. For example, if we have a vector called x that contains string such India, Russia, Indonesia then we can find the number of times character i occurred then we can use the command nchar(gsub("[^i]","",x)) and the output will be 1 1 1 because first I’s in India and Indonesia will not be considered as they are in uppercase.Example1 Live Demox1

How to find the mean squared error for linear model in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 14:01:33

4K+ Views

To find the mean squared error for linear model, we can use predicted values of the model and find the error from dependent variable then take its square and the mean of the whole output. For example, if we have a linear model called M for a data frame df then we can find the mean squared error using the command mean((df$y-predict(M))^2).Example1Consider the below data frame − Live Demox1

How to create a data frame column with letters of both size in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 13:57:25

404 Views

To create a data frame column with letters of both sizes, we can simply use the letters function and LETTERS function, the first one corresponds to lowercase letters and the latter corresponds to uppercase letters with single square brackets as shown in the below examples.Example1 Live Demodf1

How to find the index of the nearest smallest number in an R data frame column?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 13:55:20

203 Views

To find the index of the nearest smallest number in an R data frame column, we can use which function along with subsetting for the value for which we want to find the index of the nearest smallest number. To understand how it can be done check out the below examples.Example1Consider the below data frame − Live DemoID

How to convert a matrix to binary matrix in R?

Nizamuddin Siddiqui
Updated on 06-Mar-2021 13:55:48

2K+ Views

To convert a matrix to binary matrix, we can use as.matrix function and converting the matrix to logical matrix then adding 0 to the values greater than 0. For example, if we have a matrix called M then it can be converted to a binary matrix using the command −as.matrix((M

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