# LN Function

Computes the natural logarithm of an input value. The value can be a Decimal or Integer literal or a reference to a column containing numeric values.

• The natural logarithm of a value is the value of ex such that is the input value.

Wrangle vs. SQL: This function is part of Wrangle, a proprietary data transformation language. Wrangle is not SQL. For more information, see Wrangle Language.

## Basic Usage

Numeric literal example:

ln(10)

Output: Returns the value X, such that ex, is 10. This value is approximately 2.302585092994046.

Column reference example:

ln(MyValue)

Output: Returns the power to which e is raised to yield the value in the MyValue column.

## Syntax and Arguments

ln(numeric_value)

Argument

Required?

Data Type

Description

numeric_value

Y

string, decimal, or integer

Name of column or Decimal or Integer literal to apply to the function

For more information on syntax standards, see Language Documentation Syntax Notes.

### numeric_value

Name of the column or numeric literal, the natural logarithm of which is to be computed.

• Missing input values generate missing results.

• Literal numeric values should not be quoted. Quoted values are treated as strings.

• Multiple columns and wildcards are not supported.

Usage Notes:

Required?

Data Type

Example Value

Yes

String (column reference) or Integer or Decimal literal

10

## Examples

Tip

### Example - Exponential Functions

This example demonstrates the exponential functions.

Functions:

Item

Description

EXP Function

Computes the value of e raised to the specified power. The value can be a Decimal or Integer literal or a reference to a column containing numeric values.

LN Function

Computes the natural logarithm of an input value. The value can be a Decimal or Integer literal or a reference to a column containing numeric values.

LOG Function

Computes the logarithm of the first argument with a base of the second argument.

POW Function

Computes the value of the first argument raised to the value of the second argument.

Source:

rowNum

X

1

-2

2

1

3

0

4

1

5

2

6

3

7

4

8

5

Transformation:

Transformation Name New formula Single row formula EXP (X) 'expX'
Transformation Name New formula Single row formula LN (expX) 'ln_expX'
Transformation Name New formula Single row formula LOG (X) 'logX'
Transformation Name New formula Single row formula POW (10,logX) 'pow_logX'

Results:

In the following, (null value) indicates that a null value is generated for the computation.

rowNum

X

expX

ln_expX

logX

pow_logX

1

-2

0.1353352832366127

-2

(null value)

(null value)

2

-1

0.1353352832366127

-0.9999999999999998

(null value)

(null value)

3

0

1

0

(null value)

0

4

1

2.718281828459045

1

0

1

5

2

7.3890560989306495

2

0.30102999566398114

1.9999999999999998

6

3

20.085536923187668

3

0.47712125471966244

3

7

4

54.59815003314423

4

0.6020599913279623

3.999999999999999

8

5

148.41315910257657

5

0.6989700043360187

4.999999999999999