dataframe-js

### Table of Contents - [GroupedDataFrame][1] - [toCollection][2] - [show][3] - [listGroups][4] - [listHashs][5] - [map][6] - [filter][7] - [chain][8] - [aggregate][9] - [pivot][10] - [melt][11] ## GroupedDataFrame [src/groupedDataframe.js:10-276][12] Grouped DataFrame structure grouping DataFrame rows by column value. **Parameters** - `df` **DataFrame** The DataFrame to group by. - `columnNames` **...any** - `columnName` **[String][13]** The column used for the group by. ### toCollection [src/groupedDataframe.js:76-78][14] Convert GroupedDataFrame into collection (Array) of dictionnaries (Object). **Examples** ```javascript groupedDF.toCollection(); ``` Returns **[Array][15]** An Array containing group: {groupKey, group}. ### show [src/groupedDataframe.js:87-97][16] Display the GroupedDataFrame as String Table. **Parameters** - `quiet` **[Boolean][17]** Quiet mode. If true, it doesn't trigger console.log(). (optional, default `false`) **Examples** ```javascript groupedDf.show() ``` Returns **[String][13]** The GroupedDataFrame as String Table. ### listGroups [src/groupedDataframe.js:105-107][18] List GroupedDataFrame groups. **Examples** ```javascript gdf.listGroups() ``` Returns **[Array][15]** An Array containing GroupedDataFrame group names. ### listHashs [src/groupedDataframe.js:115-117][19] List GroupedDataFrame groups as a hashCode. **Examples** ```javascript gdf.listHashCodes() ``` Returns **[Array][15]** An Array containing GroupedDataFrame hash codes. ### map [src/groupedDataframe.js:126-132][20] Map on DataFrame groups. **Parameters** - `func` **[Function][21]** The function to apply to each row of each group. **Examples** ```javascript groupedDF.map((row,i) => row.set('b', row.get('a')*i)); ``` Returns **DataFrame** A new DataFrame containing the result. ### filter [src/groupedDataframe.js:141-151][22] Filter a grouped DataFrame. **Parameters** - `condition` **[Function][21]** A filter function or a column/value object. **Examples** ```javascript groupedDF.filter((row,i) => (i === 0)); ``` Returns **DataFrame** A new filtered DataFrame. ### chain [src/groupedDataframe.js:166-172][23] Chain maps and filters functions on DataFrame by optimizing their executions. If a function returns boolean, it's a filter. Else it's a map. It can be 10 - 100 x faster than standard chains of .map() and .filter(). **Parameters** - `funcs` **...[Function][21]** Functions to apply on the DataFrame rows taking the row as parameter. **Examples** ```javascript groupedDF.chain( (row, i) => (i === 0), // filter row => row.set('column1', 3), // map row => row.get('column2') === '5' // filter ) ``` Returns **DataFrame** A new DataFrame with modified rows. ### aggregate [src/groupedDataframe.js:182-190][24] Create an aggregation from a function. **Parameters** - `func` **[Function][21]** The aggregation function. - `columnName` **[String][13]** The column name created by the aggregation. (optional, default `'aggregation'`) **Examples** ```javascript groupedDF.aggregate(group => group.stat.sum('column1')); ``` Returns **DataFrame** A new DataFrame with a column 'aggregation' containing the result. ### pivot [src/groupedDataframe.js:200-228][25] Pivot a GroupedDataFrame. **Parameters** - `columnToPivot` **[String][13]** The column which will be transposed as columns. - `func` **[Function][21]** The function to define each column value from a DataFrame. (optional, default `(gdf)=>gdf.count()`) **Examples** ```javascript df.groupBy('carType').pivot('carModel', values => values.stat.sum('kms')) ``` Returns **DataFrame** The pivot DataFrame. ### melt [src/groupedDataframe.js:238-275][26] Melt a DataFrame to make it tidy. It's the reverse of GroupedDataFrame.pivot(). **Parameters** - `variableColumnName` **[String][13]** The column name containing values. (optional, default `'value'`) - `valueColumnName` (optional, default `"value"`) **Examples** ```javascript df.groupBy('carType').melt('kms') ``` Returns **DataFrame** The tidy DataFrame. [1]: #groupeddataframe [2]: #tocollection [3]: #show [4]: #listgroups [5]: #listhashs [6]: #map [7]: #filter [8]: #chain [9]: #aggregate [10]: #pivot [11]: #melt [12]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L10-L276 "Source code on GitHub" [13]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String [14]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L76-L78 "Source code on GitHub" [15]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array [16]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L87-L97 "Source code on GitHub" [17]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean [18]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L105-L107 "Source code on GitHub" [19]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L115-L117 "Source code on GitHub" [20]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L126-L132 "Source code on GitHub" [21]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function [22]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L141-L151 "Source code on GitHub" [23]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L166-L172 "Source code on GitHub" [24]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L182-L190 "Source code on GitHub" [25]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L200-L228 "Source code on GitHub" [26]: https://github.com/Gmousse/dataframe-js/blob/cef738e8a8e82e94515dfc49f015f842a8c410f2/src/groupedDataframe.js#L238-L275 "Source code on GitHub"