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DiceDB

INCRBYFLOAT

The INCRBYFLOAT command in DiceDB is used to increment the numeric value of a key by a fractional amount. This command is useful for scenarios where you need to increase a number by a fractional amount.

Syntax

Terminal window
INCRBYFLOAT key delta

Parameters

ParameterDescriptionTypeRequired
keyThe key whose value you want to increment. This key must hold a string that can be represented as an number.StringYes
deltaThe fractional value by which the key’s value should be increased. This value can be positive or negative.StringYes

Return values

ConditionReturn Value
Key exists and holds an numeric string(float) The value of the key after incrementing by delta.
Key does not exist(float) delta

Behaviour

When the INCRBYFLOAT command is executed, the following steps occur:

  • DiceDB checks if the key exists.
  • If the key does not exist, DiceDB treats the key’s value as 0 before performing the increment operation.
  • If the key exists but does not hold a string that can be represented as an number, an error is returned.
  • The value of the key is incremented by the specified increment value.
  • The new value of the key is returned.

Errors

The INCRBYFLOAT command can raise errors in the following scenarios:

  1. Wrong Type Error:

    • Error Message: ERR value is not a valid float
    • This error occurs if the increment value provided is not a valid number.
    • This error occurs if the key exists but its value is not a string that can be represented as an number

  2. Syntax Error:

    • Error Message: ERR wrong number of arguments for 'incrbyfloat' command
    • Occurs if the command is called without the required parameter.

  3. Overflow Error:

    • Error Message: (error) ERR value is out of range
    • If the increment operation causes the value to exceed the maximum float value that DiceDB can handle, an overflow error will occur.

Examples

Example with Incrementing the Value of an Existing Key

Terminal window
127.0.0.1:7379>SET mycounter 10
OK
127.0.0.1:7379>INCRBYFLOAT mycounter 3.4
"13.4"
  • In this example, the value of mycounter is set to 10
  • The INCRBYFLOAT command incremented mycounter by 3.4, resulting in a new value of 13.4

Example with Incrementing a Non-Existent Key (Implicit Initialization to 0)

Terminal window
127.0.0.1:7379>INCRBYFLOAT newcounter 5.3
"5.3"
  • In this example, since newcounter does not exist, DiceDB treats its value as 0 and increments it by 5.3, resulting in a new value of 5.3.

Example with Error Due to Wrong Value in Key

Terminal window
127.0.0.1:7379>SET mystring "hello"
OK
127.0.0.1:7379>INCRBYFLOAT mystring 2.3
(error) ERR value is not a valid float
  • In this example, the key mystring holds a string value, so the INCRBYFLOAT command returns an error.

Example with Error Due to Invalid Increment Value (Non-Integer Decrement)

Terminal window
127.0.0.1:7379>INCRBYFLOAT mycounter "two"
(error) ERR value is not a valid float
  • In this example, the increment value “two” is not a valid number, so the INCRBYFLOAT command returns an error.