Is it used to apply a function on subsets of a vector?
tapply() is used to apply a function on subsets of a vector.
Table of Contents
How do you apply a function to a vector?
How to apply functions to a vector in R
- The first argument is the vector on which you want to apply the function; in this case, the vector c(‘a’, ‘b’).
- The second argument is the name of the function; in this case, change.
- All the other arguments are just the arguments you pass to the change function.
What function is used to automatically vectorize Lapply() apply() Lapply() Sapply?
sapply() function
Function | arguments | Goal |
---|---|---|
Apply | apply(x, MARGIN, FUN) | Apply a function to rows or columns or both |
lap | lapply(X, FUN) | Apply a function to all elements of the input. |
apply sap | sapply(X, FUN) | Apply a function to all elements of the input. |
How do I create a vector function in R?
How to create a vector in R?
- Using the c() function. To create a vector, we use the c() function: Code: > vec <- c(1,2,3,4,5) #create a vector named vec.
- Using the assign() function. Another way to create a vector is the assign() function. Code:
- Using: operator. An easy way to make integer vectors is to use the : operator. Code:
How are application functions similar to a loop?
The apply family of functions provides a fairly clean syntax for applying a function (any function) to each element of some data structure. The point I want to emphasize is this: application functions are basically equivalent to loops in terms of speed. As R Inferno says: applying “is not vectorization, it’s hiding loops”.
How is the function f (x1) vectorized?
A “vectorized” function f() takes a vector [x1, x2, , xn] as input and returns the vector [f (x1), f (x2), f (x3), , f (xn)]. If you want to read more about this, you should read Chapter 3 of R Inferno, where the third circle of R hell is “can’t vectorize”. 1 Why is vectorization important?
Which is faster a vectorized function or a pure loop?
R gets a fair amount of heat from the hacker community because it’s a bit slow in loop 2. Make up (somewhat) for this weakness by using vectorized functions! Vectorized functions usually involve a behind-the-scenes loop in a low-level language (C or Fortran), which runs much faster than a pure R loop.
Can an iterator be used in the middle of a loop?
The use of an iterator is still valid. If you modify your container in the middle of your loop, the next time you use your iterator it will throw an invalid iterator exception. I was surprised that no one mentioned that iterating through an array with an integer index makes it easy to write bad code to subscript an array with the wrong index.