# Picard Plugin: Get Eval Function

**URL:** <https://community.metabrainz.org/t/picard-plugin-get-eval-function/405765>\
**Category:** MusicBrainz Picard\
**Tags:** picard-plugins-fixme\
**Created:** [November 17, 2018, 12:32am UTC](https://community.metabrainz.org/t/picard-plugin-get-eval-function/405765 "2018-11-17T00:32:32Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![rdswift](https://community.metabrainz.org/user_avatar/community.metabrainz.org/rdswift/32/7032_2.png) [@rdswift](https://community.metabrainz.org/u/rdswift)\
**Post date:** [November 17, 2018, 12:32am UTC](https://community.metabrainz.org/t/picard-plugin-get-eval-function/405765/1 "2018-11-17T00:32:32Z")

</div>

# Get Eval Function [[Download](https://github.com/rdswift/picard-plugins/raw/2.0_RDS_Plugins/plugins/get_eval/get_eval.zip)]

This plugin provides a new scripting function `$get_eval()` that allows the user to evaluate specified python code within Picard and return the results as a string for use within scripts.

This allows access to all metadata fields and the ability to use native python processing commands directly from a script without having to create and load additional plugins.

## Usage

The following are examples of some of the functionality provided by this plugin.

### Example 1

Breaks the `parser.context` metadata contents into 80-character “chunks” and creates tags named “Metadata 001”, “Metadata 002”, “Metadata 003”… containing the data chunks.

```
$get_eval(exec\('junk1 = "\%s" \% parser.context\\nfor i in range\(0\, \(len\(junk1\) // 80 \) + 1\, 1\):\\n parser.context["Metadata {0:03d}".format\(i\)] = \(junk1\)[i*80:\(i+1\)*80]\\n'\))

```

### Example 2

Lists composers for the track individually in tags “Composer 01”, “Composer 02” and so on.

```
$get_eval(exec\('for i\, j in enumerate\(parser.context["composer"].split\("; "\)\): parser.context["Composer {0:02d}".format\(i\)] = j'\))

```

### Example 3

Set the tag variable %number\_of\_composers% to the number of composers identified for the track.

```
$set(number_of_composers,$get_eval(len\(parser.context["composer"].split\("; "\)\)))

```

## Technical Notes

Access to the the metadata is provided through the `parser.context` object. All `$some_function()` functions and `%some_variable%` tag variables are expanded prior to evaluating the expression.

You can even execute code by calling the `exec()` funtion within the `$get_eval()` call.

Please see the [user guide](https://github.com/rdswift/picard-plugins/blob/2.0_RDS_Plugins/plugins/get_eval/README.md) for more information.