group_by function:

Group items by function. If the first argument is a list, return list grouped by the second argument.

Examples:

• running: (group_by ["11", "5", "23", "ab", "1", "", "100", {}], (stringify (len .))) will give: {"2": ["11", "23", "ab"], "1": ["5", "1"], "0": ["", {}], "3": ["100"]}

• running: (group_by [{"g": "one", "v": 1}, {"g": "two", "v": 2}, {"g": "one", "v": 33}, {"g": "two", "v": false}], .g) will give: {"one": [{"g": "one", "v": 1}, {"g": "one", "v": 33}], "two": [{"g": "two", "v": 2}, {"g": "two", "v": false}]}

• running: (group_by [{"g": "one", "v": 1}, {"g": "two", "v": 2}, {"g": "one", "v": 33}, {"g": "two", "v": false}], (get . ^.key)) for input: {"key": "g"} will give: {"one": [{"g": "one", "v": 1}, {"g": "one", "v": 33}], "two": [{"g": "two", "v": 2}, {"g": "two", "v": false}]} Because this group the element by a key that is taken from the input ("key").

• running: (group_by 344, (stringify (len .))) will return nothing

• running: (group_by ["11", "5", "23", "ab", "1", "", "100", {}], (len .)) will return nothing