# strtoi() Function in R: How to Convert String to Integer in R

Integers are whole numbers. Adding a character string to a numeric vector converts all the elements in the vector to the character.

## Convert String to Integer in R

To convert strings to integers in R, use the strtoi() function. The strtoi() is a built-in function that converts strings to integers. The strtoi() function accepts two arguments and returns the integers.

### Syntax

``strtoi(x, base=0L)``

### Parameters

x: It is a character vector.

base: It is an integer between 2 and 36 inclusive; default is 0. For the default base = 0L, the base is chosen from the string representing that element of x, so different elements can have different bases. The standard C rules for choosing the base are that octal constants (prefix 0 not followed by x or X) and hexadecimal constants (prefix 0x or 0X) are interpreted as base 8 and 16; all other strings are interpreted as base 10.

### Example

``````dt <- c("a", "b", "c")
ct <- c("A", "B", "C")
bt <- c("11", "21", "19")

# Calling strtoi() function for conversion
strtoi(dt, 16L)
strtoi(ct, 32L)
strtoi(bt)``````

#### Output

``````[1] 10 11 12
[1] 10 11 12
[1] 11 21 19``````

## Convert Hex Strings to Integers in R

To convert hex strings into integers, use the strtoi() function.

``````dt <- c("0xff", "023", "025")
ct <- c("0000", "FFFF")
bt <- c("260", "121")

# Calling strtoi() function for conversion
strtoi(dt)
strtoi(ct, 16L)
strtoi(bt, 8L)``````

#### Output

``````[1] 255  19  21
[1]  0   65535
[1] 176   81``````

## Convert a Character to Numeric in R

To convert a character to numeric in R, use the as.numeric() function.

``````rv <- c("-0.1", " 2.7 ", "3")
as.numeric(rv)``````

#### Output

``[1] -0.1   2.7   3.0``

That is it for converting a string to integer in R.