Logarithm in R – 4 variants to Know!

Hello, readers! In this article, we would be focusing on the Various functions of Logarithm in R programming. So let us begin!! 🙂

Logarithmic functions serve us an important aspect in terms of scaling of the data values and even in the arithmetic composition of values.

Today we will be having a look at 4 variants of Logarithmic functions in R programming:

1. log()
2. log1p()
3. log10()
4. log2()

Let us get started!!

1. R log() function

The log() function in R, returns the natural logarithmic value of the parameter passed to it. Moreover, these log values are calculated with respect to the base – e.

Let us have a look at the below example!

Example:

x = 10
res_log = log(x)
print(res_log)

In the above example, we do not specify the base value for the function. It takes ‘e’ as the default value for base while executing the function.

Output:

 2.302585

On the other hand, we can specify the value of base by setting the value of the parameter ‘base‘ in the log() function as shown below.

x = 10
res_log = log(x,base=10)
print(res_log)

Here, the log() function calculates the logarithmic values with respect to the base 10.

Output:

1

2. R log1p() function

The function log1p(y) enables us to calculate the accurate natural logarithmic value of ‘1+y‘ for any entity passed to it. If we pass 10 as the value of y, it would calculate the natural log of 1+10 with the base ‘e’.

log1p does not give us an error with 0 values. In fact, it outputs 0. On the other side, if a negative value is passed to the function, NaN would be returned.

Have a look at the below case!

Example:

res_log = log1p(10)
print(res_log)

res_log = log1p(0)
print(res_log)

res_log = log1p(-10)
print(res_log)

Output:

[1] 2.397895
[1] 0
Warning message:
In log1p(-10) : NaNs produced
[1] NaN

As you can see the results match what we mentioned before. The log1p function tries to evaluate the expressions or values to the decimal and gives an accurate representation.

3. R log10() function

R log10() function is an in-built function that calculates the natural logarithmic value of the entity considering ’10’ as the value of base for it.

The log10() function returns infinity for Zero and a NaN value for a negative entity being passed to it.

Example:

res_log = log10(10)
print(res_log)

res_log = log10(-10)
print(res_log)

res_log = log10(0)
print(res_log)

Output:

[1] 1
Warning message:
NaNs produced 
[1] NaN
[1] -Inf

5. R log2() function

On the similar lines, log2() function calculates the natural logarithmic value for an entity with respect to ‘2’ as the value of base for evaluation.

Example:

x = 100
res_log = log2(x)
print(res_log)

Output:

6.643856

Conclusion

By this, we have come to the end of this topic. In this article, we have studied the 4 IMP variants of Logarithm in R programming.

Try implementing these functions with various data values and do let us know about your understanding in the comment section.

For more such posts related to R programming, stay tuned and till then, Happy Learning!! 🙂

References

• R log() function – Documentation