INCRBYFLOAT

Introduction and Use Case(s)

The INCRBYFLOAT command in Redis increments the numeric value of a key by a specified floating-point number. It’s particularly useful for counters, real-time analytics, or any application where you need to perform precise incremental calculations.

Syntax

INCRBYFLOAT key increment

Parameter Explanations

• key: The name of the key whose value you want to increment.
• increment: The floating-point number by which to increase the key’s value. This can be a positive or negative number.

Return Values

The command returns the new value of the key after the increment. If the key does not exist, it is set to 0 before performing the operation.

Example outputs:

• If the initial value is 10.5 and you run INCRBYFLOAT key 2.3, the output will be 12.8.
• If the key does not exist and you run INCRBYFLOAT key 1.1, the output will be 1.1.

Code Examples

dragonfly> SET mykey 10.50
OK
dragonfly> INCRBYFLOAT mykey 0.10
"10.60"
dragonfly> INCRBYFLOAT mykey -5.25
"5.35"
dragonfly> GET mykey
"5.35"
dragonfly> INCRBYFLOAT newkey 1.23
"1.23"
dragonfly> GET newkey
"1.23"

Best Practices

• Ensure that the key contains a value that can be interpreted as a floating-point number to avoid errors.
• Use this command for precise increment operations, especially in applications requiring high accuracy like financial calculations or scientific data processing.

Common Mistakes

• Using INCRBYFLOAT on a key that does not store a string representation of a float will result in an error. For example, trying to use INCRBYFLOAT on a key holding non-numeric data will fail.

FAQs

What happens if the key does not exist?

If the key does not exist, INCRBYFLOAT sets it to 0 before applying the increment.

Can I decrement the value using INCRBYFLOAT?

Yes, you can decrement the value by specifying a negative increment.

What type of data does the key need to hold for INCRBYFLOAT to work?

The key should hold a string that represents a floating-point number. Any other type will result in an error.