Programming Articles - Page 924 of 3366

To find the row mean for selected columns in R data frame, we can use mutate function of dplyr package along with rowMeans function.For Example, if we have a data frame called df that contains three columns say X, Y, and Z then mean of each row for columns X and Y can be found by using the below command −df %% mutate(X_Y_Mean=select(.,c("X","Y")) %% rowMeans())Example 1Following snippet creates a sample data frame −x1

To find the column names and row names in an R data frame based on a condition, we can use row.names and colnames function. The condition for which we want to find the row names and column names can be defined inside these functions as shown in the below Examples.Example 1Following snippet creates a sample data frame −x1

To find the groupwise order of values in an R data frame, we can use mutate function of dplyr package along with rank function and grouping will be done with the help of group_by function.For Example, if we have a data frame called df that contains two columns say Group and DV then we can find the groupwise order of DV values by using the command given below −df%%group_by(Group)%%mutate(Order=rank(DV))Example 1Following snippet creates a sample data frame −Group

To create correlation matrix plot without variables labels in R, we can use tl.pos argument set to n.For Example, if we have a correlation matrix say M then we can create the correlation matrix plot without variables labels by using the below command −corrplot(M,tl.pos='n')ExampleFollowing snippet creates a sample data frame −x

Sometimes there are cases where we want to know which user is executing the current program and in which directory and we can get all these details with the help of the user package that is present inside the os package of Go's standard library.In this article, we will explore three such cases, where first, we will log out the username who is executing the current process and then we will log out the name along with the id and finally, we will log out from the directory in which the current program is located.Getting the UsernameTo get the username, ... Read More

In case we want to get the size of an array or a slice, we can make use of the built-in len() function that Go provides us with.Example 1Let's first explore how to use the len function with an array. Consider the code shown below.package main import (    "fmt" ) func main() {    fmt.Println("Inside the main function")    arr := [3]int{1, 2, 3}    fmt.Println("The length of the array is:", len(arr)) }In the above code, we are using the len function on the array defined as arr.OutputIf we run the command go run main.go ... Read More

We can close a channel in Golang with the help of the close() function. Once a channel is closed, we can't send data to it, though we can still read data from it. A closed channel denotes a case where we want to show that the work has been done on this channel, and there's no need for it to be open.We open the channel the moment we declare one using the make keyword.ch := make(chan int)Example 1Let's consider a very simple example, in which we will create a buffered channel and then pass data to it and then close ... Read More

To extract columns with a particular string in column name of an R data frame, we can use grepl function for column names and then subset the data frame with single square brackets.For Example, if we have a data frame called df and we want to extract columns that has X in their names then we can use the command mentioned below −df[grepl("X",colnames(df))]Example 1Following snippet creates a sample data frame −Students_Score

There are cases where we would want to know if the URL that we got from an http request in the form of a string is even valid or not. In such cases, one can use two functions that the net/url package of Go's standard library provides.Example 1The first basic case is to check if the URL is well structured and a valid one, and for that, we can use the ParseRequestURI() function of the URL package.Consider the code shown below.package main import (    "fmt"    "net/url" ) func main() {    u, err := url.ParseRequestURI("http://golangcode.com")   ... Read More

Splitting a string means being able to get a part of a string, and that part can either be based on a position or a character in the string.In Go, if we want to split a string on the basis of positions, we can make use of the [ ] (square brackets) and then pass the indices in them separated by a colon.SyntaxConsider the syntax shown below.sl[startingIndex : EndingIndex]It should be noted that the element at the EndingIndex in the slice won't be considered, as the range is from startingIndex to (EndingIndex−1).Example 1Now, let's consider an example where we will ... Read More