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
Suggerimento
For additional examples, see Common Tasks.
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 | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | EXP (X) |
Parameter: New column name | 'expX' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | LN (expX) |
Parameter: New column name | 'ln_expX' |
Transformation Name | |
|---|---|
Parameter: Formula type | Single row formula |
Parameter: Formula | LOG (X) |
Parameter: New column name | 'logX' |
Transformation Name | |
|---|---|
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.
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 |