Server Side Programming Articles - Page 1514 of 2650

Subsetting of factor columns can be done by creating an object of all columns using sapply with is.factor to extract only factor column in the future then passing that object into subsetting operator single square brackets. For example, if we have a data frame df that contains three columns x, y, z and two of them say x and y are factor columns then we can use Factors

In general, the default shape of points in a scatterplot is circular but it can be changed to other shapes using integers or sequence or the variable. We just need to use the argument shape inside geom_point function and pass the variable name. For example, if we want to create the scatterplot with varying shapes of a variable x then we can use geom_point(shape=x). And if we want to change the size then integer values can be used.ExampleConsider the below data frame − Live Demoset.seed(151) x

To remove the row names or column names from a matrix, we just need to set them to NULL, in this way all the names will be nullified. For example, if we have a matrix M that contain row names and column names then we can remove those names by using the command colnames(M)

The replication of matrix by rows means that repeating a matrix one or more times but row-wise. For example, if we have a matrix that contains only one row and three columns then the replication of that matrix three times will repeat that one row three times. This can be done by using rep function along with matrix function as shown in the below example.Example Live DemoM

If we have a list of website links and we want to extract the website name from those links then it is a time-consuming task because we would need to copy each name one-by-one. Therefore, it is better to extract them using a function in R and save time. To extract the website name from the website link, we can use suffix_extract function of urltools package. This will extract the host, subdomain, domain and suffix. And it is known that the domain values are the website names.Loading urltools package −library(urltools)Website links stored in a vector −Web_LinksRead More

To display a particular part of independent variable in a plot, we might want to use a horizontal line. This will make the plot look different and get the attention of the viewer. To create a horizontal line in a plot, we can use geom_line function but we need to pass the values in a data frame format for which we want to create the horizontal line.Consider the below data frame −Example Live Demox

When we import data from outside sources then the header or column names might be imported with underscore separated values and this is also possible if the original data has the same format. Therefore, to make the headers shorter and look better we would prefer to remove the underscore sign and this can be easily done with the help of gsub function.Consider the below data frame −Example Live Demox_1

In data analysis, we need to be very cautious about repeated values because they might be inputted purposely to create bias in the data and this value could be a zero as well. It happens in situations when we have missing data and the data collector replaces missing values with zeros which is a wrong practice. To find the row-wise frequency of zeros in an R data frame, we can use rowSums function for zero values by using the syntax −rowSums(“data_frame_name”==0)Consider the below data frame −Example Live Demoset.seed(189) x1

If we have many unique elements or repeated in a column of an R data frame and create a graph using that column, either on X-axis or Y-axis then R automatically choses the axes labels, this might not display all the unique values of the column in the plot. Therefore, we can use scale_x_continuous function or scale_y_continuous function with labels depending on our requirement to display the column values.Consider the below data frame −Example Live Demox

There can be multiple authors of a package in R and we might want to use their name if we are using their package in our publication for research, books, courses or any other type of content. Therefore, it is required to find out all the authors who contributed to a particular package and this can be done by using citation function with package name as shown in the below examples.Examplecitation("ggplot2")To cite ggplot2 in publications, please use −H. Wickham. ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York, 2016.A BibTeX entry for LaTeX users is@Book{,    author = {Hadley Wickham}, ... Read More