ReQL command: max

Command syntax

sequence.max(field | function) → element
sequence.max({:index => <indexname>}) → element
r.max(sequence, field | function) → element
r.max(sequence, {:index => <indexname>}) → element

Description

Finds the maximum element of a sequence.

The max command can be called with:

• a field name, to return the element of the sequence with the largest value in that field;
• an index (the primary key or a secondary index), to return the element of the sequence with the largest value in that index;
• a function, to apply the function to every element within the sequence and return the element which returns the largest value from the function, ignoring any elements where the function produces a non-existence error.

For more information on RethinkDB’s sorting order, read the section in ReQL data types.

Calling max on an empty sequence will throw a non-existence error; this can be handled using the default command.

Example: Return the maximum value in the list [3, 5, 7].

r([3, 5, 7]).max().run(conn)

Example: Return the user who has scored the most points.

r.table('users').max('points').run(conn)

Example: The same as above, but using a secondary index on the points field.

r.table('users').max({:index => 'points'}).run(conn)

Example: Return the user who has scored the most points, adding in bonus points from a separate field using a function.

r.table('users').max{|user| user['points'] + user['bonus_points']}.run(conn)

Example: Return the highest number of points any user has ever scored. This returns the value of that points field, not a document.

r.table('users').max('points')['points'].run(conn)

Example: Return the user who has scored the most points, but add a default nil return value to prevent an error if no user has ever scored points.

r.table('users').max('points').default(nil).run(conn)

Related commands

• map
• reduce
• count
• sum
• avg
• min
• group

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