FlexMatch property expressions - Amazon GameLift Servers
Common matchmaking property expressionsProperty expression examplesProperty expression aggregations
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FlexMatch property expressions

Property expressions can be used to define certain matchmaking-related properties. They allow you to use calculations and logic when defining a property value. Property expressions generally result in one of two forms:

  • Individual player data.

  • Calculated collections of individual player data.

Common matchmaking property expressions

A property expression identifies a specific value for a player, team, or match. The following partial expressions illustrate how to identify teams and players:

Goal Input Meaning Output
To identify a specific team in a match: teams[red] The Red team Team
To identify a set of specific teams in a match: teams[red,blue] The Red team and the Blue team List<Team>
To identify all teams in a match: teams[*] All teams List<Team>
To identify players in a specific team: team[red].players Players in the Red team List<Player>
To identify players in a set of specific teams in a match: team[red,blue].players Players in the match, grouped by team List<List<Player>>
To identify players in a match: team[*].players Players in the match, grouped by team List<List<Player>>

Property expression examples

The following table illustrates some property expressions that build on the previous examples:

Expression Meaning Resulting Type

teams[red].players[playerId]

 The player IDs of all players on the red team List<string>
teams[red].players.attributes[skill] The "skill" attributes of all players on the red team List<number>
teams[red,blue].players.attributes[skill] The "skill" attributes of all players on the Red team and the Blue team, grouped by team List<List<number>>
teams[*].players.attributes[skill] The "skill" attributes of all players in the match, grouped by team List<List<number>>

Property expression aggregations

Property expressions can be used to aggregate team data by using the following functions or combinations of functions:

Aggregation Input Meaning Output
min List<number> Get the minimum of all numbers in the list. number
max List<number> Get the maximum of all numbers in the list. number
avg List<number> Get the average of all numbers in the list. number
median List<number> Get the median of all numbers in the list. number
sum List<number> Get the sum of all numbers in the list. number
count List<?> Get the number of elements in the list. number
stddev List<number> Get the standard deviation of all numbers in the list. number
flatten List<List<?>> Turn a collection of nested lists into a single list containing all elements. List<?>
set_intersection List<List<string>> Get a list of strings that are found in all string lists in a collection. List<string>
All above List<List<?>> All operations on a nested list operate on each sublist individually to produce a list of results. List<?>

The following table illustrates some valid property expressions that use aggregation functions:

Expression Meaning Resulting Type
flatten(teams[*].players.attributes[skill]) The "skill" attributes of all players in the match (not grouped) List<number>
avg(teams[red].players.attributes[skill]) The average skill of the red team players number
avg(teams[*].players.attributes[skill]) The average skill of each team in the match List<number>
avg(flatten(teams[*].players.attributes[skill])) The average skill level of all players in the match. This expression gets a flattened list of player skills and then averages them. number
count(teams[red].players) The number of players on the red team number
count (teams[*].players) The number of players on each team in the match List<number>
max(avg(teams[*].players.attributes[skill])) The highest team skill level in the match number