| layout | api-command | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| language | Ruby | ||||||||||||||
| permalink | api/ruby/count/ | ||||||||||||||
| command | count | ||||||||||||||
| related_commands |
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{% apibody %} sequence.count([value | predicate_function]) → number binary.count() → number string.count() → number object.count() → number r.count(sequence | binary | string | object[, predicate_function]) → number {% endapibody %}
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)Example: Count the number of 18 year old users.
r.table('users')['age'].count(18).run(conn)Example: Count the number of users over 18.
r.table('users')['age'].count{ |age| age > 18 }.run(conn)Alternatively:
r.table('users').count{ |user| user['age'] > 18 }.run(conn)Example: Return the length of a Unicode string.
> r.expr("こんにちは").count().run(conn)
5