$$stddev

Returns the standard deviation for the values in an array

Usage

{ 
  "$$stddev": /* Array to calculate standard deviation for */,
  "default": 0 /* BigDecimal */,
  "by": "##current" /* Transformer(##current) */,
  "population": false /* boolean */
}

"$$stddev([default],[by],[population]):{input}"

note

Concrete values in the usage example are default values.

Returns

number (BigDecimal)

Arguments

Argument	Type	Values	Required / Default Value	Description
Input	array		Yes	Array to calculate standard deviation for
default	BigDecimal		0	The default value to use for empty values
by	Transformer(##current)		##current	A transformer to extract a property to get value by (using ##current to refer to the current item) ##current - Current element
population	boolean	false/true	false	Whether the input is the entire population or a sample (it will affect the calculation of variance; "n-1" for sample and "N" for population)

Examples

Input

Definition

Output

[
  1345,
  1301,
  1368,
  1322,
  1310,
  1370,
  1318,
  1350,
  1303,
  1299
]

"$$stddev:$"

27.463915719843496

Test

[
  1345,
  1301,
  1368,
  1322,
  1310,
  1370,
  1318,
  1350,
  1303,
  1299
]

"$$stddev:$"

27.463915719843496

Test

[
  {
    "value": 1345
  },
  {
    "value": 1301
  },
  {
    "value": 1368
  },
  {
    "value": 1322
  },
  {
    "value": 1310
  },
  {
    "value": 1370
  },
  {
    "value": 1318
  },
  {
    "value": 1350
  },
  {
    "value": 1303
  },
  {
    "value": 1299
  }
]

{
  "$$stddev": "$",
  "by": "##current.value"
}

27.463915719843496

Test

[
  {
    "value": 1345
  },
  {
    "value": 1301
  },
  {
    "value": 1368
  },
  {
    "value": 1322
  },
  {
    "value": 1310
  },
  {
    "value": 1370
  },
  {
    "value": 1318
  },
  {
    "value": 1350
  },
  {
    "value": 1303
  },
  {
    "value": 1299
  }
]

{
  "$$stddev": "$",
  "by": "##current.value",
  "population": true
}

26.054558142482478

Test