# KTHLARGESTUNIQUE Function

Extracts the ranked unique value from the values in a column, where `k=1`

returns the maximum value. The value for `k`

must be between 1 and 1000, inclusive. Inputs can be Integer, Decimal, or Datetime.

For purposes of this calculation, two instances of the same value are treated as the same value of `k`

. So, if your dataset contains four rows with column values`10`

,`9`

,`9`

, and `8`

, then`KTHLARGEST`

returns`9`

for`k=2`

and `8`

for `k=3`

.

For a non-unique version of this function, see KTHLARGEST Function.

When used in a`pivot`

transform, the function is computed for each instance of the value specified in the`group`

parameter. See Pivot Transform.

Input column can be of Integer, Decimal, or Datetime type. Other values column are ignored. If a row contains a missing or null value, it is not factored into the calculation.

**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

kthlargestunique(myRating, 3)

**Output:** Returns the third highest unique value from the `myRating`

column.

## Syntax and Arguments

kthlargestunique(function_col_ref, k_integer) [ 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 |

k_integer | Y | integer (positive) | The ranking of the unique value to extract from the source column |

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 mean. Inputs must be Integer, Decimal, or Datetime values.

**注記**

If the input is in Datetime type, the output is in unixtime format. You can wrap these outputs in the DATEFORMAT function to output the results in the appropriate Datetime format. See DATEFORMAT Function.

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) | myValues |

### k_integer

Integer representing the ranking of the unique value to extract from the source column. Duplicate values are treated as a single value for purposes of this function's calculation.

**注記**

The value for `k`

must be an integer between 1 and 1,000 inclusive.

`k=1`

represents the maximum value in the column.If k is greater than or equal to the number of values in the column, the minimum value is returned.

Missing and null values are not factored into the ranking of

`k`

.

** Usage Notes:**

Required? | Data Type | Example Value |
---|---|---|

Yes | Integer (positive) | 4 |

## Examples

**ヒント**

For additional examples, see Common Tasks.

This example explores how you can use aggregation functions to calculate rank of values in a column.

**Functions**:

Item | Description |
---|---|

KTHLARGEST Function | Extracts the ranked value from the values in a column, where |

KTHLARGESTUNIQUE Function | Extracts the ranked unique value from the values in a column, where |

**Source:**

You have a set of student test scores:

Student | Score |
---|---|

Anna | 84 |

Ben | 71 |

Caleb | 76 |

Danielle | 87 |

Evan | 85 |

Faith | 92 |

Gabe | 87 |

Hannah | 99 |

Ian | 73 |

Jane | 68 |

**Transformation:**

You can use the following transformations to extract the 1st through 4th-ranked scores on the test:

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGEST(Score, 1) |

Parameter: New column name | '1st' |

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGEST(Score, 2) |

Parameter: New column name | '2nd' |

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGEST(Score, 3) |

Parameter: New column name | '3rd' |

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGEST(Score, 4) |

Parameter: New column name | '4th' |

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGESTUNIQUE(Score, 3) |

Parameter: New column name | '3rdUnique' |

Transformation Name | |
---|---|

Parameter: Formula type | Single row formula |

Parameter: Formula | KTHLARGESTUNIQUE(Score, 4) |

Parameter: New column name | '4thUnique' |

**Results:**

When you reorganize the columns, the dataset might look like the following:

Student | Score | 1st | 2nd | 3rd | 4th | 3rdUnique | 4thUnique |
---|---|---|---|---|---|---|---|

Anna | 84 | 99 | 92 | 87 | 87 | 87 | 85 |

Ben | 71 | 99 | 92 | 87 | 87 | 87 | 85 |

Caleb | 76 | 99 | 92 | 87 | 87 | 87 | 85 |

Danielle | 87 | 99 | 92 | 87 | 87 | 87 | 85 |

Evan | 85 | 99 | 92 | 87 | 87 | 87 | 85 |

Faith | 92 | 99 | 92 | 87 | 87 | 87 | 85 |

Gabe | 87 | 99 | 92 | 87 | 87 | 87 | 85 |

Hannah | 99 | 99 | 92 | 87 | 87 | 87 | 85 |

Ian | 73 | 99 | 92 | 87 | 87 | 87 | 85 |

Jane | 68 | 99 | 92 | 87 | 87 | 87 | 85 |

Notes:

The value

`87`

is both the third and fourth scores.For the

`KTHLARGEST`

function, it is the output for the third and fourth ranking.For the

`KTHLARGESTUNIQUE`

function, it is the output for the third ranking only.