JMESPath · lesson 12 of 15 · Functions

Counting & math

length, avg, min, max and sum work on arrays (and length works on strings and objects too).

Example 1Count, average, youngest, oldest

Document

{
  "team": "Platform",
  "office": { "city": "Berlin", "floor": 3 },
  "members": [
    { "name": "Ada", "age": 36, "role": "lead", "active": true,
      "email": "[email protected]", "skills": ["rust", "sql"] },
    { "name": "Linus", "age": 28, "role": "dev", "active": true,
      "email": null, "skills": ["c", "shell"] },
    { "name": "Grace", "age": 45, "role": "dev", "active": false,
      "skills": ["cobol"] },
    { "name": "Alan", "age": 41, "role": "qa", "active": true,
      "email": "[email protected]", "skills": [] }
  ]
}

Query

[length(members), avg(members[*].age), min(members[*].age), max(members[*].age)]

length(members) How many members → 4.
avg(members[*].age) The mean age → 37.5.
min(members[*].age) The youngest → 28.
max(members[*].age) The oldest → 45.

Result

[4,37.5,28,45]

Try it in the playground

Good to know

sum is there too — and, like abs, it returns a floating-point number: sum(members[*].age) prints 150.0.