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orange / docs / widgets / rst / data / file.rst

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File

File widget icon

Reads attribute-value data from an input file.

Signals

Inputs:
  • (None)
Outputs:
  • :obj:`Data`

    Attribute-valued data set read from the input file.

Description

File widget reads the input data file (data table with data instances) and sends the data set to its output channel. It maintains a history of most recently opened files. For convenience, the history also includes a directory with the sample data sets that come pre-installed with Orange.

The widget reads data from simple tab-delimited or comma-separated files, as well as files in Weka's arrf format.

File widget with loaded Iris data set
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Advanced Options

Advanced options of File widget
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Tab-delimited data file can include user defined symbols for undefined values. The symbols for "don't care" and "don't know" values can be specified in the corresponding edit lines. The default values for "don't know" and "don't care" depend upon format. Most users will use tab-delimited files: keep the field empty or put a question mark in there and that's it. Most algorithms do not differ between don't know and don't care values, so consider them both to mean undefined.

Orange will usually treat the attributes with the same name but appearing in different files as the same attribute, so a classifier which uses the attribute "petal length" from the first will use the attribute of the same name from the second. In cases when attributes from different files just accidentally bear different names, one can instruct Orange to either always construct new attribute or construct them when they differ in their domains. Use the options on dealing with new attributes with great care (if at all).

Example

Most Orange workflows would probably start with the File widget. In the schema below, the widget is used to read the data that is sent to both :ref:`Data Table` widget and to widget that displays :ref:`Attribute Statistics`.

Example schema with File widget