## What does tapply mean in R?

tapply in R. Apply a function to each cell of a ragged array, that is to each (non-empty) group of values given by a unique combination of the levels of certain factors. Basically, tapply() applies a function or operation on subset of the vector broken down by a given factor variable.

## What does the Tapply () function do?

tapply() is used to apply a function over subsets of a vector. It is primarily used when we have the following circumstances: A dataset that can be broken up into groups (via categorical variables – aka factors) We desire to break the dataset up into groups.

**How does Sapply work in R?**

The sapply in R is a built-in function that applies a function to all the input elements. The sapply() method takes a list, vector, or data frame as an argument and returns a vector or matrix. The sapply() is an R wrapper class to lapply, with the difference being it returns a vector or matrix instead of a list object.

**What is the output of tapply?**

By default, if the applied function returns a scalar, then tapply returns a vector. In this case we are applying the mean function, so the output of tapply is a numeric vector. tapply(x, f, mean) # Take the mean of each group. Returns a vector.

### What is the difference between Lapply and Sapply?

Difference between lapply() and sapply() functions: lapply() function displays the output as a list whereas sapply() function displays the output as a vector. lapply() and sapply() functions are used to perform some operations in a list of objects.

### Why does Sapply return a list?

The real reason for this is that sapply doesn’t know what your function will return without calling it. In your case the function returns a logical , but since sapply is given an empty list, the function is never called. Therefore, it has to come up with a type and it defaults to list .

**What is difference between Lapply and Sapply?**

**What does summary () do in R?**

summary() function in R Language is a generic function used to produce result summaries of the results of various model fitting functions.

#### How do I count in R studio?

count() lets you quickly count the unique values of one or more variables: df %>% count(a, b) is roughly equivalent to df %>% group_by(a, b) %>% summarise(n = n()) . count() is paired with tally() , a lower-level helper that is equivalent to df %>% summarise(n = n()) .

#### What does Sapply stand for?

simplify

1. Bookmark this question. Show activity on this post. There seems to be general agreement that the l in “lapply” stands for list, the s in “sapply” stands for simplify and the r in “rapply” stands for recursively.

**Do call vs Lapply?**

lapply applies a function to all elements of a list, do. call calls a function where all the function arguments are in a list.

**How do you use Tapply in R with multiple factors?**

Tapply in R with multiple factors You can apply the tapply function to multiple columns (or factor variables) passing them through the list function. In this example, we are going to apply the tapply function to the type and store factors to calculate the mean price of the objects by type and store. tapply(price, list(type, store), mean)

## How to check the length of Tapply arguments?

Note that the tapply arguments must have the same length. You can verify it with the length function. It also should be noticed that the default output is of class “array”. Hence, if needed, you can access each element of the output specifying the desired index in square brackets.

## What does Tapply return when fun does not return an atomic value?

If FUN does not return a single atomic value, tapply returns an array of mode list whose components are the values of the individual calls to FUN, i.e., the result is a list with a dim attribute.

**Does Tapply always return a scalar?**

logical; if FALSE, tapply always returns an array of mode “list”; in other words, a list with a dim attribute. If TRUE (the default), then if FUN always returns a scalar, tapply returns an array with the mode of the scalar. When FUN is present, tapply calls FUN for each cell that has any data in it.