ReQL command: count

Command syntax

sequence.count([value | predicate_function]) → number
binary.count() → number
string.count() → number
object.count() → number
array.count() → number
r.count(sequence | binary | string | object[, predicate_function]) → number

Description

Counts the number of elements in a sequence or key/value pairs in an object, or returns the size of a string or binary object.

When count is called on a sequence with a predicate value or function, it returns the number of elements in the sequence equal to that value or where the function returns true. On a binary object, count returns the size of the object in bytes; on strings, count returns the string’s length. This is determined by counting the number of Unicode codepoints in the string, counting combining codepoints separately.

Example: Count the number of users.

r.table('users').count().run(conn, callback);

Example: Count the number of 18 year old users.

r.table('users')('age').count(18).run(conn, callback);

Example: Count the number of users over 18.

r.table('users')('age').count(function(age) { 
    return age.gt(18)
}).run(conn, callback);

r.table('users').count(function(user) {
    return user('age').gt(18)
}).run(conn, callback)

Example: Return the length of a Unicode string.

r.expr("こんにちは").count().run(conn, callback);
// Result passed to callback
5

Example: Return the length of an array.

r.expr(['0','1','2']).count().run(conn, callback);
// Result passed to callback
3