1. Apprendre
    2. /
  2. Cours
    3. /
  3. Intermediate R
  • 1

    Conditionals and Control Flow

    Gratuit

    In this chapter, you'll learn about relational operators for comparing R objects, and logical operators like "and" and "or" for combining TRUE and FALSE values. Then, you'll use this knowledge to build conditional statements.

  • 2

    Loops

    Loops can come in handy on numerous occasions. While loops are like repeated if statements, the for loop is designed to iterate over all elements in a sequence. Learn about them in this chapter.

  • 3

    Functions

    Functions are an extremely important concept in almost every programming language, and R is no different. Learn what functions are and how to use them—then take charge by writing your own functions.

  • 4

    The apply family

    Whenever you're using a for loop, you may want to revise your code to see whether you can use the lapply function instead. Learn all about this intuitive way of applying a function over a list or a vector, and how to use its variants, sapply and vapply.

  • 5

    Utilities

    Mastering R programming is not only about understanding its programming concepts. Having a solid understanding of a wide range of R functions is also important. This chapter introduces you to many useful functions for data structure manipulation, regular expressions, and working with times and dates.

Initializing

Exercice

Use vapply (2)

So far you've seen that vapply() mimics the behavior of sapply() if everything goes according to plan. But what if it doesn't?

In the video, Filip showed you that there are cases where the structure of the output of the function you want to apply, FUN, does not correspond to the template you specify in FUN.VALUE. In that case, vapply() will throw an error that informs you about the misalignment between expected and actual output.

Instructions

100 XP
  • Inspect the pre-loaded code and try to run it. If you haven't changed anything, an error should pop up. That's because vapply() still expects basics() to return a vector of length 3. The error message gives you an indication of what's wrong.
  • Try to fix the error by editing the vapply() command.