eval_match() evaluates how desirable a matching result is
for a specified player.
eval_match(x, name, group = NULL, preference)An object of the "matching" class obtained by matching or
matching_df().
A character string of the name of a player to be evaluated.
This argument determines whether the specified player belongs to
the proposers or the proposed. If a proposing player and a proposed
player have the same name, this argument must be either "proposer" or
"proposed" in order to uniquely identify the player. If all players have
a unique name, this can be set to NULL. Default is NULL.
A vector representing the preference of the player.
The first, second, third, ... element of the vector is the players' first,
second, third, ... choice. For example, If the player preferes A to B to
C, this argument should be c("A", "B", "C").
An integer value indicating the rank of the match given their true preference. NA will be returned if there is no match.