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Trifacta Dataprep


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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 e x 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 e x, 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)


ArgumentRequired?Data TypeDescription
numeric_valueYstring, decimal, or integerName 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 TypeExample Value
YesString (column reference) or Integer or Decimal literal10

Examples

Tip: For additional examples, see Common Tasks.

Example - Exponential Functions

The following example demonstrates how the exponential functions work together. These functions include the following:

Source:

rowNumX
1-2
21
30
41
52
63
74
85

Transformation:


Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula EXP (X)
Parameter: New column name 'expX'

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula LN (expX)
Parameter: New column name 'ln_expX'

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula LOG (X)
Parameter: New column name 'logX'

Transformation Name New formula
Parameter: Formula type Single row formula
Parameter: Formula POW (10,logX)
Parameter: New column name 'pow_logX'

Results:

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

rowNumXexpXln_expXlogXpow_logX
1-20.1353352832366127-2(null value)(null value)
2-10.1353352832366127-0.9999999999999998(null value)(null value)
3010(null value)0
412.718281828459045101
527.389056098930649520.301029995663981141.9999999999999998
6320.08553692318766830.477121254719662443
7454.5981500331442340.60205999132796233.999999999999999
85148.4131591025765750.69897000433601874.999999999999999

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