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Player Variables

Related Config File Sections:

MPF contains lots of features which make working with players easy including variables. If you are not a programmer, variables are just locations inside the computer's memory to store bits of information like numbers and text (aka strings). Programmers create variables to store and retrieve these bit of information for use in their programs. For example, You may want to create a player variable to store the number of times a bumper has been hit to award a bumper bonus.

Each player has "player variables" which are key/value pairs that are stored separately for each player.

Some simple examples of player variables include things like:

  • number: The player's number (1, 2, etc.)
  • score: The player's current score

There are two types of player variables that you can use; the default player variables provided by MPF and custom variables that you can create, update and reference.

Default Player Variables

There's a Player Variables Reference which lists the default player variables that MPF creates and uses.

MPF also uses player variables to keep track of all the built-in game logic elements that are tracked on a per-player basis, including achievement status, logic block states, extra balls, bonus, etc.

Custom Player Variables

You can also create your own custom player variables which can be called anything you want and can store anything you want. You can use them to track player's progress through the game, how many loops they've made, how many pop bumper hits they have, etc. See the player_vars: documentation for details and examples.

Data types

If you are a programmer, you likely know what datatypes are. If you are not a programmer but want to create your own player variables, you'll need to know a little bit about datatypes. To make this really simple, you may want to store the name of the current mode so that you can display the mode name on the display. Since the name of the mode is a piece of text, you'll need to create a player variable of type "str" to denote a string of characters. Here are the data types available in MPF.

Datatype Description

str a string of textual characters

int an integer, a basic number with no decimal point

float floating point, a more precise number with decimal point


    initial_value: Trees Attack
    value_type: str
    initial_value: 0
    value_type: int
    initial_value: 1.25
    value_type: float

Player varaibles are essentially global in MPF, meaning that you can define them in config files and they are available to use in any location in your files. This makes them easy to use but also easy to introduce bugs or unintended consequences so be aware of every place that you use them if you are getting unanticipated results. A best practice would be to define all of your player variables in a common location such as the machine configuration file.

Setting Variables

MPF configuration files do not work with variables as easily as "real" programming languages. The primary method of changing a variable is by configuring the change you would like to make. In the current version of MPF, this is primarily done in the variable_player: section of your mode.

##! mode: my_mode
  # add 1 to bumper_hits
    bumper_hits: 1

The example below shows a player variable of type string being updated. A mode carousel (mode selection by the player) was used by the player to select a mode ladder (a set of modes played in a sequence similar to scenes in GhostBusters). The apostrophes are not required but allowed.

##! mode: my_mode
      action: set
      string: 'Scene 1'

The example below shows a player variable being updated after a conditional event. In this case, the base mode has received an event indicated that a mode has been complete. The conditional event checks to see which mode ladder was in play and increments the custom player variable ladder_scene_1 to indicate the progress towards completing the mode.

##! mode: my_mode
  mode_is_complete{current_player.current_ladder=="Scene 1"}:
    ladder_scene_1: 1

Displaying Custom Variables

Displaying your custom player variables on a slide can be confusing in the current version of MPF. The example below shows a text widget that is displaying 3 variables on the main scoring screen of the base mode. The first two variables are of type "str" and the last variable is of type "int".

    initial_value: "Initial Ladder"
    value_type: str
    initial_value: "No Mode"
    value_type: str
    initial_value: 1
    value_type: int

##! mode: base
      - type: text
        text: (current_ladder) > (current_mode) > (ladder_scene_1)
##! test
#! start_game
#! start_mode base
#! advance_time_and_run .1
#! assert_text_on_top_slide "Initial Ladder > No Mode > 1"

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