# Get the Log of a Value in R – With Examples

In this tutorial, we will look at how to compute the logarithm of a value using log functions in R with the help of some examples.

## How to compute the log of a value in R?

You can use the built-in `log()` function to compute the log of a value in R. Pass the value for which you want to compute the log as an argument. The following is the syntax –

```# log function in R
log(x, base)```

The `log()` function takes the following arguments –

• `x` – The value for which you want to compute the log.
• `base` (optional) – The logarithmic base to use.

By default, the `log()` function computes the natural log of a value if you don’t specify the base. If you specify the base, it computes the log with respect to the given base.

Note that R also has direct functions to compute the logarithm with common bases such as `log10()` to compute log with 10 as the base and `log2()` to compute log with 2 as the base.

## Examples

Let’s look at some examples of using the above functions in R.

To get the natural log of a value in R, pass the value to the `log()` function without any additional arguments. For example, let’s compute the natural log of some numbers using this method –

```# natural log of value
print(log(1))
print(log(2))```

Output:

``` 0
 0.6931472```

We get the natural log of 1 as 0 and 2 as 0.693.

### Log with base 10 in R

Let’s now compute the log with base 10 for a value. For this, you can either directly use the `log10()` function or use the `log()` function with `base=10`.

Let’s look at an example.

```# log with base 10
print(log10(100))
print(log(100, 10))```

Output:

``` 2
 2```

Here, we compute the log with base 10 of the number 100 using the functions `log10()` and `log()` (with the base as 10). You can see that we get the same result from both methods.

### Log with base 2 in R

You can similarly compute the log with base 2 for a value in R. That is, either directly use the `log2()` function or use the `log()` function with `base=2`.

Let’s look at an example.

```# log with base 2
print(log2(8))
print(log(8, 2))```

Output:

``` 3
 3```

Here, we compute the log with base 2 of the number 8 using the functions `log2()` and `log()` (with the base as 2). You can see that we get the same result from both methods.

### Log with custom base for a value in R

As shown above, you can use the `log()` function with a custom base value. For example, let’s compute the log of 9 with base 3.

```# log with custom base
print(log(9, 3))```

Output:

` 2`

We get 2 as the output.

In this tutorial, we looked at how to compute the logarithm of a value in R using the function `log()` which computes the natural log by default but can be customized to compute the log with respect to a different base using the `base` parameter. We also looked at some specific log functions such as `log10()` and `log2()` which compute the log with respect to base 10 and 2 respectively.

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## Authors

• Piyush is a data scientist passionate about using data to understand things better and make informed decisions. In the past, he's worked as a Data Scientist for ZS and holds an engineering degree from IIT Roorkee. His hobbies include watching cricket, reading, and working on side projects.

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