R Advanced

Whether you are reading or writing files via programs in the file system, it is necessary to check if that file already exists. If you don’t put a check in place, it can lead to either a program crash or an error. Checking if the file exists The most efficient way to check if the … Read more

The zip() function creates a new zip archive file. You must ensure that the zip tool is available in your system to work with zip() functions. For example, Windows and Mac systems have built-in zip tools, but Linux does not have a tool; you need to install it separately. Then, you can use this zip() function … Read more

When working with file systems, checking the directory or file existence is always better before commencing the operations. For a directory To create a directory, if it does not exist, use the dir.exists() function. After checking its existence, if it does not exist, you can use the dir.create() function to create a new directory with a specified … Read more

Calculating Standard Deviation (SD) by group in a Data Frame essentially means finding the SD of a specific numeric column separately for each unique categorical variable (column) or group. It allows us to see how the data variability differs across the groups. Here are three ways to calculate SD by group: Using dplyr Using data.table … Read more

When we say summarise multiple columns, it means aggregate the input data by applying summary functions (sum, mean, max, etc.) to multiple numeric columns simultaneously. The below image describes visually: If grouping is required, you can group by a specific categorical column and get the statistics for each group. The dplyr package provides the summarise() … Read more

Cumulative sum by group means for each group, we calculate the running sum of values in the specific column that increases with each row within that group. It is the following two-step process: First, divide the data into subgroups based on single or multiple grouping variables (categorical variables). Within each subgroup, calculate the sum of … Read more

Finding the minimum value by group means getting the smallest value within each group in our data frame. For example, if I have a column that I defined as a “group” and another column called “value” that contains different numeric values, then I will extract the minimum value from the value column for each distinct … Read more

If you want to find the maximum value within a specific subset of your data, you must find the maximum value within each group. First, you need to group your data based on the values of one or more categorical variables (columns). The second step is identifying the maximum value of a specific numeric variable … Read more

Counting conditionally in the data frame means counting the number of rows that meet specific conditions defined by the user. It is the process of determining the number of rows based on certain conditions evaluated to TRUE. You can count a number of rows conditionally in a data frame using base R functions, dplyr methods, … Read more

What do you mean by counting unique values by group? Well, it means you divide the dataset into subsets based on the values of one or more categorical variables (columns), and within each subset, you determine the number of distinct (unique) values in a specific column. Here are three ways to count unique values by group: … Read more