$exp

O $exp operador retorna o valor de e elevado ao expoente especificado. A constante matemática e é aproximadamente igual a 2,71828.

Sintaxe

{
  $exp: <exponent>
}

Parâmetros

Parâmetro	Description
<exponent>	Qualquer expressão válida que seja resolvida para um número.

Examples

Considere este documento de exemplo da coleção de lojas.

{
    "_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
    "name": "First Up Consultants | Beverage Shop - Satterfieldmouth",
    "location": {
        "lat": -89.2384,
        "lon": -46.4012
    },
    "staff": {
        "totalStaff": {
            "fullTime": 8,
            "partTime": 20
        }
    },
    "sales": {
        "totalSales": 75670,
        "salesByCategory": [
            {
                "categoryName": "Wine Accessories",
                "totalSales": 34440
            },
            {
                "categoryName": "Bitters",
                "totalSales": 39496
            },
            {
                "categoryName": "Rum",
                "totalSales": 1734
            }
        ]
    },
    "promotionEvents": [
        {
            "eventName": "Unbeatable Bargain Bash",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 6,
                    "Day": 23
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 7,
                    "Day": 2
                }
            },
            "discounts": [
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 7
                },
                {
                    "categoryName": "Bitters",
                    "discountPercentage": 15
                },
                {
                    "categoryName": "Brandy",
                    "discountPercentage": 8
                },
                {
                    "categoryName": "Sports Drinks",
                    "discountPercentage": 22
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 19
                }
            ]
        },
        {
            "eventName": "Steal of a Deal Days",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 21
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 29
                }
            },
            "discounts": [
                {
                    "categoryName": "Organic Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "White Wine",
                    "discountPercentage": 20
                },
                {
                    "categoryName": "Sparkling Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 17
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 23
                }
            ]
        }
    ]
}

Exemplo 1 - Calcular a taxa de crescimento exponencial

Para calcular a taxa de crescimento exponencial do volume total de vendas de uma loja em 10% e 20% respectivamente, use o operador $exp para multiplicar o valor do campo totalSales por e^0.1 e e^0.2.

db.stores.aggregate([{
        $match: {
            _id: "40d6f4d7-50cd-4929-9a07-0a7a133c2e74"
        }
    },
    {
        $project: {
            name: 1,
            currentSales: "$sales.totalSales",
            projectedGrowth: {
                oneYear: {
                    $multiply: [
                        "$sales.totalSales",
                        {
                            $exp: 0.1
                        } // 10% growth rate
                    ]
                },
                twoYears: {
                    $multiply: [
                        "$sales.totalSales",
                        {
                            $exp: 0.2
                        } // 20% growth rate
                    ]
                }
            }
        }
    }
])

Essa consulta retorna o seguinte resultado:

[
  {
    "_id": "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
    "name": "Proseware, Inc. | Home Entertainment Hub - East Linwoodbury",
    "currentSales": 151864,
    "projectedGrowth": {
      "oneYear": 167809.93,
      "twoYears": 185304.95
    }
  }
]