Merger - Documentation

Constructor

new Merger()

Source:

data.js, line 3274

This is the Data.Merger class.
It realizes an object to load two or more data sources and merge the data guided by 2 columns with identical values.

Example

var merger = new Data.Merger()
     .addSource(prezzi,{lookup:"idImpianto",columns:["descCarburante","prezzo","isSelf","dtComu"]});
     .addSource(impianti,{lookup:"idImpianto",columns:["Bandiera","Latitudine","Longitudine"]});
		.realize(
	function(mergedTable) {

		selection = mergedTable.select("WHERE tipo_riga == LI");
		 ...
	});

Returns:

a new Data.Merger object

Methods

addSource(source, option)

Source:

data.js, line 3294

add one source to the merger

Examples

.addSource(prezzi,{lookup:"idImpianto",columns:["descCarburante","prezzo","isSelf","dtComu"]});

.addSource(prezzi,{lookup:"idImpianto",columns:["descCarburante","prezzo","isSelf","dtComu"],label:["CARB1","PREZZO","SELF","COM"]});

Parameters:

Name	Type	Description
`source`	object	a loaded data.js table object, typically the result of a data.feed
`option`	object	the merging parameter for this sorce: lookup, columns and label [optional]

Returns:

the Data.Merger object

error(onError)

Source:

data.js, line 3494

define error function

Example

var merger= new Data.Merger()
     .addSource("https://raw.githubusercontent.com/ondata/elezionipolitiche2018/master/dati/scrutiniCI_cm.csv","csv")

     .error(function(e){alert(e);})

     .realize(
	function() {
         ...
	});

Parameters:

Name	Type	Description
`onError`	function	a user defined function to call when error occurs

Returns:

the Data.Merger object

realize(callback)

Source:

data.js, line 3332

See:

Data.Merger.setCallback

initiates the process of merging the sources, guided by the lookup column, inserting all columns that have been defined by .addSource(), or a subset
of them defined by .setOutputColumns()

Example

...
.realize(function(newData){
    ixmaps.setExternalData(newData,{"type":"jsonDB","name":"prezzi_tipo_latlon"});
});

Parameters:

Name	Type	Description
`callback`	function	user defined function which receives as argument the merged table

setOutputColumns(columnsA)

Source:

data.js, line 3314

define which source columns should be included into the merged table.

Example

var merger = new Data.Merger()
     .addSource(prezzi,{lookup:"idImpianto",columns:["descCarburante","prezzo","isSelf","dtComu"]});
     .addSource(impianti,{lookup:"idImpianto",columns:["Bandiera","Latitudine","Longitudine"]});
		.setOuputColumns(["desCaburante","prezzo"])
     .realize();

Parameters:

Name	Type	Description
`columnsA`	array	a subset of source columns or label you defined by .addSource

Returns:

the Data.Merger object