R Advanced

The colMeans() function in R calculates the arithmetic mean of columns in a numeric matrix, data frame, or array. It efficiently calculates the average value for each column by summing the elements and dividing by the number of elements (or non-missing elements if specified). In the above figure, we defined an input data frame, df, … Read more

The rowMeans() is a built-in, highly vectorized function in R that computes the arithmetic mean of values in each row of a numeric matrix or a data frame (with numeric-like columns). Ensure that the object passed to rowMeans() is numeric or can be coerced to numeric. If it contains non-numeric columns, it will throw an … Read more

The colSums() function in R calculates the sums of columns for numeric matrices, data frames, or arrays. In this figure, we calculated the sum of each column in the data frame. For col1, the sum of values is (1 + 2 + 3) 6. For col2, the sum of values is (4 + 5 + … Read more

The rowSums() function calculates the sum of values in each numeric row of a matrix, array, or data frame. It quickly sums up data across rows without having to write loops, making it faster and more memory-efficient than manual iteration. In the above figure, we showed the sum of each row in a data frame … Read more

The View() is a utility function in R that invokes a more intuitive spreadsheet-style data viewer on a matrix-like R object. View() does not print output in the console or return a value — it is a side-effect function that launches a separate data viewer window. It is ideal for quickly checking data contents, identifying patterns, or … Read more

The summary() is a generic function that produces the summary statistics for various R objects, including vectors, matrices, data frames, and model objects. The above figure explains the summary for a data frame with three columns. For different types of objects, the summary() function produces different types of summaries: If the input is numeric, it … Read more

Standard Error (SE) measures the variability or dispersion of the sample mean estimate of a population mean. Here are three ways to calculate standard error in R: Using sd() with length() Using the standard error formula Using std.error() from plotrix package Here is the basic formula: where: σ = sample standard deviation n = sample … Read more

The pnorm() function in R calculates the cumulative density function (cdf) value of the normal distribution given a specific random variable q, the population mean μ, and the population standard deviation σ. It returns the probability that a normally distributed random variable is less than or equal to a given value. It provides the probability … Read more

Set the current working directory The setwd() function sets the working directory to the new location, allowing us to change the default location for file operations. The working directory is a location where R looks for files to read or save by default. Use absolute paths for reliability, relative paths for flexibility. Syntax setwd(dir) Parameters … Read more

The sd() function in R calculates the sample standard deviation of a numeric vector or an object, excluding factors. It uses Bessel’s correction (n-1). The standard deviation is a measure that tells you how spread out the data is in a dataset. It is a measurement of the dispersion of the values. If the standard … Read more