Contents:
- If a row contains a missing or null value, it is not factored into the calculation. If the entire column contains no values, the function returns a null value.
- When used in a
pivottransform, the function is computed for each instance of the value specified in thegroupparameter. See Pivot Transform.
Quartiles are computed as follows:
| Quartile | Description |
|---|---|
| 0 | Minimum value |
| 1 | 25th percentile |
| 2 | Median value |
| 3 | 75th percentile and higher |
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
<span>quartile</span>(myScores, 3, linear)
Output: Computes the value that is at the 3rd quartile across all values in the myScores column.
Syntax and Arguments
quartile(function_col_ref,num_quartile,interpolation_method) [group:group_col_ref] [limit:limit_count]
| Argument | Required? | Data Type | Description |
|---|---|---|---|
| function_col_ref | Y | string | Name of column to which to apply the function |
| num_quartile | Y | integer | Integer value (0-3) of the quartile to compute |
| interpolation_method | Y | enum | Method by which to interpolate values between two row values. See below. |
For more information on the group and limit parameters, see Pivot Transform.
For more information on syntax standards, see Language Documentation Syntax Notes.
function_col_ref
Name of the column the values of which you want to calculate the quartile. Column must contain Integer or Decimal values.
- Literal values are not supported as inputs.
- Multiple columns and wildcards are not supported.
Usage Notes:
| Required? | Data Type | Example Value |
|---|---|---|
| Yes | String (column reference) | precipitationIn
|
num_quartile
Integer literal value indicating the quartile that you wish to compute. Input value must be between 0 and 3, inclusive.
- Column or function references are not supported.
- Multiple columns and wildcards are not supported.
Usage Notes:
| Required? | Data Type | Example Value |
|---|---|---|
| Yes | Integer | 3 |
interpolation_method
Method of interpolation between each discrete value. The list of support methods is the following:
| Interpolation method | Description |
|---|---|
linear | Quartiles are calculated between two discrete values in a linear fashion. |
exclusive | Excludes 0 (0th percentile) and 1 (100th percentile) from calculation of quartiles. |
inclusive | Includes 0 (0th percentile) and 1 (100th percentile) from calculation of quartiles. |
lower | Use the lower value when the computed value falls between two discrete values. |
upper | Use the upper value when the computed value falls between two discrete values. |
midpoint | Use the midpoint value when the computed value falls between two discrete values. |
Usage Notes:
| Required? | Data Type | Example Value |
|---|---|---|
| Yes | Enum | linear |
Tip: For additional examples, see Common Tasks.
Examples
Example - Percentile functions
MEDIAN- Calculate the median value from a column of values. See MEDIAN Function.PERCENTILE- Calculate a specified percentile for a column of values. See PERCENTILE Function.QUARTILE- Calculate a specified quartile for a column of values. See QUARTILE Function.
The following functions use an approximation technique for calculating median, percentile, and quartiles. In some cases, these calculations can be computed faster across large datasets.
APPROXIMATEMEDIAN- Calculate a close approximation of the median value from a column of values. See APPROXIMATEMEDIAN Function.APPROXIMATEPERCENTILE- Calculate a close approximation of a specified percentile for a column of values. See APPROXIMATEPERCENTILE Function.APPROXIMATEQUARTILE- Calculate a close approximation of a specified quartile for a column of values. See APPROXIMATEQUARTILE Function.
Source:
The following table lists each student's height in inches:
| Student | Height |
|---|---|
| 1 | 64 |
| 2 | 65 |
| 3 | 63 |
| 4 | 64 |
| 5 | 62 |
| 6 | 66 |
| 7 | 66 |
| 8 | 65 |
| 9 | 69 |
| 10 | 66 |
| 11 | 73 |
| 12 | 69 |
| 13 | 69 |
| 14 | 61 |
| 15 | 64 |
| 16 | 61 |
| 17 | 71 |
| 18 | 67 |
| 19 | 73 |
| 20 | 66 |
Transformation:
Use the following transformations to calculate the median height in inches, a specified percentile and the first quartile.
- The first function uses a precise algorithm which can be slow to execute across large datasets.
- The second function uses an appropriate approximation algorithm, which is much faster to execute across large datasets.
- These approximate functions can use an error boundary parameter, which is set to
0.4(0.4%) across all functions.
- These approximate functions can use an error boundary parameter, which is set to
Median: This transformation calculates the median value, which corresponds to the 50th percentile.
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | median(heightIn) |
| Parameter: New column name | 'medianIn' |
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | approximatemedian(heightIn, 0.4) |
| Parameter: New column name | 'approxMedianIn' |
Percentile: This transformation calculates the 68th percentile.
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | percentile(heightIn, 68, linear) |
| Parameter: New column name | 'percentile68In' |
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | approximatepercentile(heightIn, 68, 0.4) |
| Parameter: New column name | 'approxPercentile68In' |
Quartile: This transformation calculates the first quartile, which corresponds to the 25th percentile.
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | quartile(heightIn, 1, linear) |
| Parameter: New column name | 'percentile25In' |
| Transformation Name | New formula |
|---|---|
| Parameter: Formula type | Single row formula |
| Parameter: Formula | approximatequartile(heightIn, 1, 0.4) |
| Parameter: New column name | 'approxPercentile25In' |
Results:
| studentId | heightIn | approxPercentile25In | percentile25In | approxPercentile68In | percentile68In | approxMedianIn | medianIn |
|---|---|---|---|---|---|---|---|
| 1 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 2 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 3 | 63 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 4 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 5 | 62 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 6 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 7 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 8 | 65 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 9 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 10 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 11 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 12 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 13 | 69 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 14 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 15 | 64 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 16 | 61 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 17 | 71 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 18 | 67 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 19 | 73 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
| 20 | 66 | 64 | 64 | 67.1 | 66.92 | 66 | 66 |
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