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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to standardize matrix elements in R?
The standardization is the process of converting a value to another value so that the mean of the set of values from which the original value was taken becomes zero and the standard deviation becomes one. To standardize matrix elements, we can use data.Normalization function of clusterSim package but we need to make sure that we set the type argument to n1 because that corresponds to standardization with mean zero and standard deviation 1.Loading clusterSim package −library("clusterSim")ExampleM1
Read MoreHow to display the values of two columns of an R data frame separately in a plot?
In general, the scatterplot is used to visualize the relationship between two columns of an R data frame but if we want to display the two columns separately not as a pair then we need to use matplot function. This function will create a plot for all the values in the two columns and represent them by their column number.Consider the below data frame −Exampleset.seed(222) x
Read MoreHow to populate select list with jQuery?
To populate select list with jQuery, use for loop along with append() and append the options to the already created select.Let’s say we have the following select with options − John David ExampleFollowing is the code to append more number of options using append() − Document John David $(document).ready(function () { var data = [ { "name": "Bob", "customerName": "Bob" }, { "name": "Mike", "customerName": "Mike" } ]; for (var index = 0; index
Read MoreHow to create a subset of a matrix in R using row names?
When we create a matrix in R, the row names and column names are not defined but we can define them separately. If we want to take a subset of rows of a matrix then row numbers can be used within single square brackets but if we want to do it with the names then we need to specify those names.ExampleM1
Read MoreHow to combine year, month, and day column in an R data frame?
Sometimes date variable is recorded in three different columns representing year, month, and day instead of a single column as date. Therefore, we need to combine these three columns and create a single column. This can be done by using paste function and define the values with as.Date.Consider the below data frame −ExampleYear
Read MoreHow to replace NA values in columns of an R data frame form the mean of that column?
In the whole world, the first step people teach to impute missing values is replacing them with the relevant mean. That means if we have a column which has some missing values then replace it with the mean of the remaining values. In R, we can do this by replacing the column with missing values using mean of that column and passing na.rm = TRUE argument along with the same.Consider the below data frame −Exampleset.seed(121) x
Read MoreHow to create a string vector with numbers at the end in R?
If we want to create a categorical vector with all unique values representing strings with numbers at the end then paste0 function can help us in the same. For example, if we want to create a vector for ID up to 10 as ID1, ID2, ID3, ID4, ID5, ID6, ID7, ID8, ID9, and ID10 then it can be done as paste0("ID",seq(1:10)).Examplex1
Read MoreHow to save an R data frame as txt file?
If we want to use a data frame created in R in the future then it is better to save that data frame as txt file because it is obvious that data creation takes time. This can be done by using write.table function. For example, if we have a data frame df then we can save it as txt file by using the code write.table(df,"df.txt",sep="\t",row.names=FALSE)Consider the below data frame −Exampleset.seed(111) x1
Read MoreHow to find the correlation coefficient between rows of two data frames in R?
It is common the find the correlation coefficient between columns of an R data frame but we might want to find the correlation coefficient between rows of two data frames. This might be needed in situations where we expect that there exists some relationship row of an R data frame with row of another data frame. For example, row of an R data frame showing buying trend of a customer in one year and the same row of the other data frame showing buying trend of the same customer in another year.Consider the below data frame −Examplex1
Read MoreHow to find the sum of anti-diagonal elements in a matrix in R?
The anti-diagonal elements in a matrix are the elements that form straight line from right upper side to right bottom side. For example, if we have a matrix as shown below −1 2 3 4 5 6 7 8 9then the diagonal elements would be 1, 5, 9 and the anti-diagonal elements would be 3, 5, 7.To find the sum of these anti-diagonal elements, we can use apply function.ExampleM1
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