Top questions with answers asked in MNC on R Language

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R language interview questions along with their answers:

  1. What is R language, and what are its key features?
    • Answer: R is a programming language and environment specifically designed for statistical computing and data analysis. Its key features include:
      • Extensive libraries and packages for statistical analysis, machine learning, data visualization, and more.
      • Interactive environment with a command-line interface (CLI) and integrated development environment (IDE) like RStudio.
      • Ability to handle large datasets and perform complex data manipulations.
      • Open-source and cross-platform, with a large and active community contributing to its development and support.
  2. How do you read data from a CSV file in R?
    • Answer: In R, you can read data from a CSV file using the read.csv() function. Here’s an example:

      R

      data <- read.csv("filename.csv")

      This function reads the CSV file specified by "filename.csv" and stores the data in the variable data.

  3. What are factors in R, and why are they useful?
    • Answer: Factors in R are used to represent categorical data, such as levels of a factor variable (e.g., “Male” and “Female”). They are useful because:
      • They provide efficient storage and manipulation of categorical data.
      • They ensure that data analysis functions treat categorical variables correctly, such as in statistical modeling or plotting.
      • They facilitate the creation of ordered factors, where the levels have a natural order (e.g., “low,” “medium,” “high”).
  4. Explain the difference between == and === operators in R.
    • Answer:
      • The == operator is used for testing exact equality between two objects. It returns TRUE if the two objects are equal, and FALSE otherwise.
      • The === operator is used for testing object identity. It returns TRUE if the two objects are identical (i.e., they refer to the same underlying memory location), and FALSE otherwise.
  5. How do you install and load packages in R?
    • Answer: To install packages in R, you can use the install.packages() function. For example:

      R

      install.packages("package_name")

      To load packages into your R session, you can use the library() function. For example:

      R

      library(package_name)

      This function loads the specified package into memory, making its functions and datasets available for use in your R scripts or sessions.