array_find.json

{
    "id": "array_find",
    "summary": "Get the index for a value in an array",
    "description": "Returns the zero-based index of the first (or last) occurrence of the value specified by `value` in the array specified by `data` or `null` if there is no match. Use the parameter `reverse` to switch from the first to the last match.\n\n**Remarks:**\n\n* Use ``array_contains()`` to check if an array contains a value regardless of the position.\n* Use ``array_find_label()`` to find the index for a label.\n* All definitions for the process ``eq()`` regarding the comparison of values apply here as well. A `null` return value from ``eq()`` is handled exactly as `false` (no match).\n* Data types MUST be checked strictly. For example, a string with the content *1* is not equal to the number *1*.\n* An integer *1* is equal to a floating-point number *1.0* as `integer` is a sub-type of `number`. Still, this process may return unexpectedly `false` when comparing floating-point numbers due to floating-point inaccuracy in machine-based computation.\n* Temporal strings are treated as normal strings and MUST NOT be interpreted.\n* If the specified value is an array, object or null, the process always returns `null`. See the examples for one to find `null` values.",
    "categories": [
        "arrays",
        "reducer"
    ],
    "parameters": [
        {
            "name": "data",
            "description": "List to find the value in.",
            "schema": {
                "type": "array",
                "items": {
                    "description": "Any data type is allowed."
                }
            }
        },
        {
            "name": "value",
            "description": "Value to find in `data`. If the value is `null`, this process returns always `null`.",
            "schema": {
                "description": "Any data type is allowed."
            }
        },
        {
            "name": "reverse",
            "description": "By default, this process finds the index of the first match. To return the index of the last match instead, set this flag to `true`.",
            "schema": {
                "type": "boolean"
            },
            "default": false,
            "optional": true
        }
    ],
    "returns": {
        "description": "The index of the first element with the specified value. If no element was found, `null` is returned.",
        "schema": [
            {
                "type": "null"
            },
            {
                "type": "integer",
                "minimum": 0
            }
        ]
    },
    "examples": [
        {
            "arguments": {
                "data": [
                    1,
                    2,
                    3,
                    2,
                    3
                ],
                "value": 2
            },
            "returns": 1
        },
        {
            "arguments": {
                "data": [
                    1,
                    2,
                    3,
                    2,
                    3
                ],
                "value": 2,
                "reverse": true
            },
            "returns": 3
        },
        {
            "arguments": {
                "data": [
                    "A",
                    "B",
                    "C"
                ],
                "value": "b"
            },
            "returns": null
        },
        {
            "arguments": {
                "data": [
                    1,
                    2,
                    3
                ],
                "value": "2"
            },
            "returns": null
        },
        {
            "arguments": {
                "data": [
                    1,
                    null,
                    2,
                    null
                ],
                "value": null
            },
            "returns": null
        },
        {
            "arguments": {
                "data": [
                    [
                        1,
                        2
                    ],
                    [
                        3,
                        4
                    ]
                ],
                "value": [
                    1,
                    2
                ]
            },
            "returns": null
        },
        {
            "arguments": {
                "data": [
                    [
                        1,
                        2
                    ],
                    [
                        3,
                        4
                    ]
                ],
                "value": 2
            },
            "returns": null
        },
        {
            "arguments": {
                "data": [
                    {
                        "a": "b"
                    },
                    {
                        "c": "d"
                    }
                ],
                "value": {
                    "a": "b"
                }
            },
            "returns": null
        }
    ],
    "links": [
        {
            "rel": "example",
            "type": "application/json",
            "href": "https://raw.githubusercontent.com/Open-EO/openeo-community-examples/main/processes/array_find_nodata.json",
            "title": "Find no-data values in arrays"
        }
    ]
}