Logarithm: natural / arbitrary base (log)

[ 1 Description ] [ 2 How does it work in the search window? ] [ 3 How does it work in LINQ? ]

Description

Returns the base-e logarithm of the selected number. Optionally, you can add a second argument to calculate the log base x of a given number.

How does it work in the search window?

Select Create column in the search window toolbar, then select the Logarithm: natural / arbitrary base operation. You need to specify at least one argument:

Argument	Data type

Argument	Data type
Argument ^mandatory	integer, float
Base	integer, float

The data type of the values in the new column is float.

Example

We want to get the base-e logarithm of the numbers in our posNumbers1 column. To do it, we will create a new column using the Logarithm: natural / arbitrary base operation.

First, we must transform the string values in the posNumbers1 column into a data type integer. To do it, create a new column using the To Int operation. Call the new column integerValues.

Now, create another column using the Logarithm: natural / arbitrary base operation. The arguments needed to create the new column are:

Argument - integerValues column

Click Create column and you will see the following result:

How does it work in LINQ?

Use the operator select... as... and add the operation syntax to create the new column. This is the syntax for the Logarithm: natural / arbitrary base operation:

log(number)
log(base_number, number)

Example

You can copy the following LINQ script and try the above example on the my.upload.sample.data table.

from my.upload.sample.data
select split(message, ";", 17) as posNumbers1
select int(posNumbers1) as integerValues
  select log(integerValues) as loge