# R Programming language - R ifelse() Function

In R programming language, the `ifelse()`

function is a vectorized version of the `if...else`

statement, which allows you to apply the `if...else`

logic to each element of a vector or array.

The general syntax of the `ifelse()`

function is as follows:

ifelse(condition, true_value, false_value)

The `condition`

is a Boolean expression that evaluates to either TRUE or FALSE. If the condition is TRUE, the `true_value`

is returned; otherwise, the `false_value`

is returned.

Here is an example of using the `ifelse()`

function in R:

x <- c(1, 2, 3, 4, 5) ifelse(x > 3, "high", "low")

In this example, the `condition`

is `x > 3`

. Since the first three elements of `x`

are less than or equal to 3, and the last two elements are greater than 3, the output will be a character vector of length 5, with the first three elements set to "low" and the last two elements set to "high".

You can also use nested `ifelse()`

functions to test multiple conditions. The general syntax for nested `ifelse()`

functions is as follows:

ifelse(condition1, true_value1, ifelse(condition2, true_value2, ifelse(condition3, true_value3, false_value)))

Here is an example of a nested `ifelse()`

function in R:

x <- c(1, 2, 3, 4, 5) ifelse(x > 3, "high", ifelse(x == 3, "medium", "low"))

In this example, the first `condition`

is `x > 3`

, the second `condition`

is `x == 3`

, and the `false_value`

is "low". Since the first three elements of `x`

are less than or equal to 3, the output will be a character vector of length 5, with the first three elements set to "low", the fourth element set to "high", and the fifth element set to "high".