$divide (expression operator)（表达式运算符）

Definition定义

$divide

Divides one number by another and returns the result. Pass the arguments to $divide in an array.将一个数字除以另一个数字并返回结果。将参数传递给数组中的$divide。

The $divide expression has the following syntax:$divide表达式具有以下语法：

{ $divide: [ <expression1>, <expression2> ] }

The first argument is the dividend, and the second argument is the divisor; i.e. the first argument is divided by the second argument.第一个参数是股息，第二个参数是除数；即第一个参数被第二个参数所分割。

The arguments can be any valid expression as long as they resolve to numbers. 参数可以是任何有效的表达式，只要它们解析为数字。For more information on expressions, see Expressions.有关表达式的详细信息，请参阅表达式。

Behavior行为

The default return type is a double. If at least one operand is a decimal, then the return type is a decimal.默认返回类型是double。如果至少有一个操作数是decimal，则返回类型是decimal。

Examples示例

Consider a conferencePlanning collection with the following documents:考虑一个包含以下文件的conferencePlanning（会议策划）集合：

db.conferencePlanning.insertMany( [
   { "_id" : 1, "city" : "New York", "hours" : 80, "tasks" : 7 },
   { "_id" : 2, "city" : "Singapore", "hours" : 40, "tasks" : 4 }
] )

The following aggregation uses the $divide expression to divide the hours field by a literal 8 to compute the number of work days:以下聚合使用$divide表达式将hours字段除以文字8来计算工作日数：

db.planning.aggregate(
   [
     { $project: { city: 1, workdays: { $divide: [ "$hours", 8 ] } } }
   ]
)

The operation returns the following results:该操作返回以下结果：

{ "_id" : 1, "city" : "New York", "workdays" : 10 }
{ "_id" : 2, "city" : "Singapore", "workdays" : 5 }