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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to take a random sample from a matrix in R?
To take a random sample from a matrix in R, we can simply use sample function and if the sample size is larger than the number of elements in the matrix replace=TRUE argument will be used.For example, if we have a matrix called M that contains 100 elements and we want to sample 200 elements from M then we can use the below given command −sample(M,200,replace=TRUE)Example 1Following snippet creates a matrix −M1
Read MoreHow to subset R data frame rows and keep the rows with NA in the output?
To subset R data frame rows and keep the rows with NA in the output, we can use subset function along with OR condition with | sign for na values.For example, if we have a data frame called df that contains a column say C which has some NA values then we can subset df for values greater than 5 and include NA in the output by using the below given command −subset(df,C>5|is.na(C))Example 1Following snippet creates a sample data frame −x1
Read MoreHow to create a column of raise to the power of another column in data frames stored in R list?
To create a column of raise to the power of another column in data frames stored in R list, we can follow the below steps −First of all, create a list of data frames.Then, use lapply function to create a column of raise to the power of another column in data frames stored in the list.ExampleCreate the list of data framesUsing data.frame function to create data frames and list function to create the list of those data frames −df1
Read MoreHow to change the axis ticks color in base R plot?
To change the axis ticks color in base R plot, we can use axis function after creating the plot. For example if we want to change the color of X-axis to red then we can use the command given below −axis(1, col.ticks="red")If we want to change the color of Y-axis to red then we can use the command given below −axis(2, col.ticks="red") Check out the below given example to understand how it works.ExampleTo change the axis ticks color in base R plot, use the code given below −plot(1:10)OutputIf you execute the above given code, it generates the following output −To ...
Read MoreHow to select data.table object columns based on their class in R?
To select data.table object columns based on their class in R, we can follow the below steps −First of all, create a data.table object.Then, use str function to check the structure of the object.After that, use select_if function from dplyr package to select the columns based on their class.Example 1Create the data.table objectLet’s create a data.table object as shown below −library(data.table) x1
Read MoreHow to remove dollar sign from a column of a data.table object in R?
To remove dollar sign in data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use gsub function along with lapply function to remove dollar sign.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) Sale_Price
Read MoreHow to add rows in an R data frame?
To add rows in an R data frame, we can follow the below steps −First of all, create a data frame.Then, use rbind function and the vectors that will be added as rows to the data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to find the percent of zeros in each row of an R data frame?
To find the percent of zeros in each row of an R data frame, we can follow the below steps −First of all, create a data frame.Then, use rowSums function along with ncol function to find the percent of zeros in each row of the data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to subset an R data frame by ignoring a value in one of the columns?
To subset an R data frame by ignoring a value in one of the columns, we can follow the below steps −First of all, create a data frame.Then, use single square brackets to subset the data frame by ignoring a value in one of the columns.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to remove percentage sign at last position from every value in R data frame column?
To remove percentage sign at last position from every value in R data frame column, we can follow the below steps −First of all, create a data frame with a column having percent sign at last position in every value.Then, use gsub function to remove the percent sign at last position from every value in the column.ExampleCreate the data frameLet’s create a data frame as shown below −var
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