# Apply function to each row in Data.table in R

In this article, we are going to see how to apply functions to each row in the data.table in R Programming Language.

For applying a function to each row of the given data.table, the user needs to call the apply() function which is the base function of R programming language, and pass the required parameter to this function to be applied in each row of the given data.table in R language.

**apply()** function returns a vector or array or list of values obtained by applying a function to the margins of an array or matrix.

Syntax:apply(X, MARGIN, FUN, …)

Parameters:

- X: an array, including a matrix.
- MARGIN: a vector giving the subscripts which the function will be applied over.
- FUN: the function to be applied: see ‘Details’. In the case of functions like +, %*%, etc., the function name must be backquoted or quoted.
- …: optional arguments to FUN.

**Example 1:**

## R

`library` `(data.table)` ` ` `gfg_data <- ` `data.table` `(x = ` `c` `(1,2,3,4,5), ` ` ` `y = ` `c` `(4,3,2,5,1),` ` ` `z=` `c` `(2,3,5,4,1))` ` ` `gfg_data ` `apply` `(gfg_data, 1, sum)` |

**Output:**

[1] 7 8 10 13 7

**Example 2:**

## R

`library` `(data.table)` ` ` `gfg_data <- ` `data.table` `(x = ` `c` `(1,2,3,4,5), ` ` ` `y = ` `c` `(4,3,2,5,1),` ` ` `z=` `c` `(2,3,5,4,1))` ` ` `gfg_data ` `apply` `(gfg_data, 1, max)` |

**Output:**

[1] 4 3 5 5 5