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

The examples in this article use values in a data table generated from the following CSV file.

If you want to try the example for yourself, download the file and upload it to your domain clicking Data upload in the navigation pane. Name the new table my.upload.sample.data and select Current date as Date parsing type. Learn more about uploading data in Uploading log files.

After receiving the confirmation message, you can access the table from the Finder, selecting my → upload → sample → data. When you upload data from a file, all the information is included in a single column called message. To split the values and extract those we need for this operation into a new column, you can use the Split operation. Click Toggle Query Editor in the search window toolbar and paste the following LINQ query to get the information required for the examples below:

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

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 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