count.json

{
    "id": "count",
    "summary": "Count the number of elements",
    "description": "Gives the number of elements in an array that matches the specified condition.\n\n**Remarks:**\n\n* Counts the number of valid elements by default (`condition` is set to `null`). A valid element is every element for which ``is_valid()`` returns `true`.\n* To count all elements in a list set the `condition` parameter to boolean `true`.",
    "categories": [
        "arrays",
        "math > statistics",
        "reducer"
    ],
    "parameters": [
        {
            "name": "data",
            "description": "An array with elements of any data type.",
            "schema": {
                "type": "array",
                "items": {
                    "description": "Any data type is allowed."
                }
            }
        },
        {
            "name": "condition",
            "description": "A condition consists of one or more processes, which in the end return a boolean value. It is evaluated against each element in the array. An element is counted only if the condition returns `true`. Defaults to count valid elements in a list (see ``is_valid()``). Setting this parameter to boolean `true` counts all elements in the list. `false` is not a valid value for this parameter.",
            "schema": [
                {
                    "title": "Condition",
                    "description": "A logical expression that is evaluated against each element in the array.",
                    "type": "object",
                    "subtype": "process-graph",
                    "parameters": [
                        {
                            "name": "x",
                            "description": "The value of the current element being processed.",
                            "schema": {
                                "description": "Any data type."
                            }
                        },
                        {
                            "name": "context",
                            "description": "Additional data passed by the user.",
                            "schema": {
                                "description": "Any data type."
                            },
                            "optional": true,
                            "default": null
                        }
                    ],
                    "returns": {
                        "description": "`true` if the element should increase the counter, otherwise `false`.",
                        "schema": {
                            "type": "boolean"
                        }
                    }
                },
                {
                    "title": "All elements",
                    "description": "Boolean `true` counts all elements in the list.",
                    "type": "boolean",
                    "const": true
                },
                {
                    "title": "Valid elements",
                    "description": "`null` counts valid elements in the list.",
                    "type": "null"
                }
            ],
            "default": null,
            "optional": true
        },
        {
            "name": "context",
            "description": "Additional data to be passed to the condition.",
            "schema": {
                "description": "Any data type."
            },
            "optional": true,
            "default": null
        }
    ],
    "returns": {
        "description": "The counted number of elements.",
        "schema": {
            "type": "number"
        }
    },
    "examples": [
        {
            "arguments": {
                "data": []
            },
            "returns": 0
        },
        {
            "arguments": {
                "data": [
                    1,
                    0,
                    3,
                    2
                ]
            },
            "returns": 4
        },
        {
            "arguments": {
                "data": [
                    "ABC",
                    null
                ]
            },
            "returns": 1
        },
        {
            "arguments": {
                "data": [
                    false,
                    null
                ],
                "condition": true
            },
            "returns": 2
        },
        {
            "arguments": {
                "data": [
                    0,
                    1,
                    2,
                    3,
                    4,
                    5,
                    null
                ],
                "condition": {
                    "gt": {
                        "process_id": "gt",
                        "arguments": {
                            "x": {
                                "from_parameter": "element"
                            },
                            "y": 2
                        },
                        "result": true
                    }
                }
            },
            "returns": 3
        }
    ]
}