HSTRLEN command in Redis is used when we want to retrieve the length of the value of a hash field. This command is useful when developing applications that require a check on the length of stored data without retrieving the entire value, such as limiting text input or monitoring data size.
Let's assume you're using the
redis gem in Ruby. Here's an example usage of the
In this example, we first create a new Redis object. Then, we set a hash with the key
myhash and a field
field1 with the value
Hello World. Lastly, we use
hstrlen to get the length of the value of
field1, which is 11 ('Hello World' is 11 characters long).
HSTRLENto prevent unnecessary exceptions.
HSTRLENsparingly in performance-critical parts of your code, as it might result in additional round trips to the server if not used in conjunction with other commands.
HSTRLENreturns the length of the string value, not the count of hash fields or their keys.
HSTRLENwill return zero for non-existing keys or fields. In reality, it returns
Q: What does
HSTRLEN return if the key or field does not exist?
HSTRLEN command will return
nil if the key or the field does not exist.
Q: Does the
HSTRLEN command change any data in Redis?
A: No, the
HSTRLEN command is a read-only command and does not modify any data stored in Redis.