aggregate_by_key {dataPreparation} | R Documentation |

## Automatic data_set aggregation by key

### Description

Automatic aggregation of a data_set set according to a `key`

.

### Usage

```
aggregate_by_key(data_set, key, verbose = TRUE, thresh = 53, ...)
```

### Arguments

`data_set` |
Matrix, data.frame or data.table (with only numeric, integer, factor, logical, character columns) |

`key` |
Name of a column of data_set according to which the set should be aggregated (character) |

`verbose` |
Should the algorithm talk? (logical, default to TRUE) |

`thresh` |
Number of max values for frequencies count (numerical, default to 53) |

`...` |
Optional argument: |

### Details

Perform aggregation depending on column type:

If column is numeric

`functions`

are performed on the column. So 1 numeric column give length(functions) new columns,If column is character or factor and have less than

`thresh`

different values, frequency count of values is performed,If column is character or factor with more than

`thresh`

different values, number of different values for each`key`

is performed,If column is logical, number of TRUE is computed.

In all cases, if the set as more rows than unique `key`

, a number of lines will be computed.

Be careful using functions argument, given functions should be an aggregation function, meaning that for multiple values it should only return one value.

### Value

A `data.table`

with one line per `key`

elements and multiple new columns.

### Examples

```
## Not run:
# Get generic dataset from R
data("adult")
# Aggregate it using aggregate_by_key, in order to extract characteristics for each country
adult_aggregated <- aggregate_by_key(adult, key = 'country')
# Example with other functions
power <- function(x) {sum(x^2)}
adult_aggregated <- aggregate_by_key(adult, key = 'country', functions = c("power", "sqrt"))
# sqrt is not an aggregation function, so it wasn't used.
## End(Not run)
# "##NOT RUN:" mean that this example hasn't been run on CRAN since its long. But you can run it!
```

*dataPreparation*version 1.1.1 Index]