array

Documentation

Overview

Package array Array Expression Operators

Index

• func ArrayElemAt[A expression.ArrayExpression, I expression.IntExpression](array A, idx I) arrayOperator
• func ArrayToObject[A expression.ArrayExpression](array A) arrayOperator
• func ConcatArrays[A expression.ArrayExpression](arrays ...A) arrayOperator
• func Filter[A expression.ArrayExpression, T expression.BooleanExpression, ...](array A, cond T, as string, limit N) arrayOperator
• func First[A expression.ArrayExpression](array A) arrayOperator
• func FirstN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator
• func In[A expression.ArrayExpression, T expression.AnyExpression](e T, array A) arrayOperator
• func IndexOfArray[A expression.ArrayExpression, T expression.AnyExpression](array A, search T, options IndexOfArrayOptions) arrayOperator
• func IsArray[T expression.AnyExpression](a T) arrayOperator
• func Last[A expression.ArrayExpression](array A) arrayOperator
• func LastN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator
• func Map[A expression.ArrayExpression, T expression.AnyExpression](input A, in T, as string) arrayOperator
• func MaxN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator
• func MinN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator
• func Range[N expression.IntExpression](start, end N, step int32) arrayOperator
• func Reduce[A expression.ArrayExpression, T expression.AnyExpression](input A, initialValue, in T) arrayOperator
• func ReverseArray[A expression.ArrayExpression](input A) arrayOperator
• func Size[A expression.ArrayExpression](input A) arrayOperator
• func Slice[A expression.ArrayExpression, N expression.IntExpression](input A, position, n N) arrayOperator
• func SortArray[A expression.ArrayExpression](input A, sortBy bsonx.Bson) arrayOperator
• func Zip[A expression.ArrayExpression](inputs []A, useLongestLength bool, defaults []A) arrayOperator
• type IndexOfArrayOptions

Functions

func ArrayElemAt

func ArrayElemAt[A expression.ArrayExpression, I expression.IntExpression](array A, idx I) arrayOperator

ArrayElemAt Returns the element at the specified array index. $arrayElemAt has the following syntax: { $arrayElemAt: [ <array>, <idx> ] } The <array> expression can be any valid expression that resolves to an array. The <idx> expression can be any valid expression that resolves to an integer.

func ArrayToObject

func ArrayToObject[A expression.ArrayExpression](array A) arrayOperator

ArrayToObject Converts an array into a single document; the array must be either: An array of two-element arrays where the first element is the field name, and the second element is the field value: [ [ [ "item", "abc123" ], [ "qty", 25 ] ] ] - OR - An array of documents that contains two fields, k and v where: The k field contains the field name. The v field contains the value of the field. [ [ { "k": "item", "v": "abc123" }, { "k": "qty", "v": 25 } ] ]

func ConcatArrays

func ConcatArrays[A expression.ArrayExpression](arrays ...A) arrayOperator

ConcatArrays Concatenates arrays to return the concatenated array. $concatArrays has the following syntax: { $concatArrays: [ <array1>, <array2>, ... ] } The <array> expressions can be any valid expression as long as they resolve to an array. For more information on expressions, see Expressions. If any argument resolves to a value of null or refers to a field that is missing, $concatArrays returns null.

func Filter

func Filter[A expression.ArrayExpression, T expression.BooleanExpression, N expression.NumberExpression](array A, cond T, as string, limit N) arrayOperator

Filter Selects a subset of an array to return based on the specified condition. Returns an array with only those elements that match the condition. The returned elements are in the original order.

func First

func First[A expression.ArrayExpression](array A) arrayOperator

First New in version 4.4. Returns the first element in an array. $first has the following syntax: { $first: <expression> } The <expression> can be any valid expression as long as it resolves to an array, null or missing. For more information on expressions, see Expressions. The $first operator is an alias for the following $arrayElemAt expression: { $arrayElemAt: [ <array expression>, 0 ] }

func FirstN

func FirstN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator

FirstN New in version 5.2. Returns a specified number of elements from the beginning of an array. $firstN has the following syntax: { $firstN: { n: <expression>, input: <expression> } }

func In

func In[A expression.ArrayExpression, T expression.AnyExpression](e T, array A) arrayOperator

In Returns a boolean indicating whether a specified value is in an array. $in has the following operator expression syntax: { $in: [ <expression>, <array expression> ] }

func IndexOfArray

func IndexOfArray[A expression.ArrayExpression, T expression.AnyExpression](array A, search T, options IndexOfArrayOptions) arrayOperator

IndexOfArray Searches an array for an occurrence of a specified value and returns the array index (zero-based) of the first occurrence. If the value is not found, returns -1. $indexOfArray has the following operator expression syntax: { $indexOfArray: [ <array expression>, <search expression>, <start>, <end> ]

func IsArray

func IsArray[T expression.AnyExpression](a T) arrayOperator

IsArray Determines if the operand is an array. Returns a boolean. $isArray has the following syntax: { $isArray: [ <expression> ] }

func Last

func Last[A expression.ArrayExpression](array A) arrayOperator

Last New in version 4.4. Returns the last element in an array. The $last operator has the following syntax: { $last: <expression> } The <expression> can be any valid expression as long as it resolves to an array, null, or missing. For more information on expressions, see Expressions. The $last operator is an alias for the following $arrayElemAt expression: { $arrayElemAt: [ <array expression>, -1 ] }

func LastN

func LastN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator

LastN New in version 5.2. Returns a specified number of elements from the end of an array. $lastN has the following syntax: { $lastN: { n: <expression>, input: <expression> } }

func Map

func Map[A expression.ArrayExpression, T expression.AnyExpression](input A, in T, as string) arrayOperator

Map Applies an expression to each item in an array and returns an array with the applied results. The $map expression has the following syntax: { $map: { input: <expression>, as: <string>, in: <expression> } }

func MaxN

func MaxN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator

MaxN New in version 5.2. Returns the n largest values in an array. $maxN has the following syntax: { $maxN: { n: <expression>, input: <expression> } }

func MinN

func MinN[A expression.ArrayExpression, N expression.IntExpression](array A, n N) arrayOperator

MinN New in version 5.2. Returns the n smallest values in an array. $minN has the following syntax: { $minN: { n: <expression>, input: <expression> } }

func Range

func Range[N expression.IntExpression](start, end N, step int32) arrayOperator

Range Returns an array whose elements are a generated sequence of numbers. $range generates the sequence from the specified starting number by successively incrementing the starting number by the specified step value up to but not including the end point. $range has the following operator expression syntax: { $range: [ <start>, <end>, <non-zero step> ] }

func Reduce

func Reduce[A expression.ArrayExpression, T expression.AnyExpression](input A, initialValue, in T) arrayOperator

Reduce Applies an expression to each element in an array and combines them into a single value. $reduce has the following syntax:

{
   $reduce: {
       input: <array>,
       initialValue: <expression>,
       in: <expression>
   }
}

func ReverseArray

func ReverseArray[A expression.ArrayExpression](input A) arrayOperator

ReverseArray Accepts an array expression as an argument and returns an array with the elements in reverse order. $reverseArray has the following operator expression syntax: { $reverseArray: <array expression> } The argument can be any valid expression as long as it resolves to an array.

func Size

func Size[A expression.ArrayExpression](input A) arrayOperator

Size Counts and returns the total number of items in an array. $size has the following syntax: { $size: <expression> } The argument for $size can be any expression as long as it resolves to an array. For more information on expressions, see Expressions.

func Slice

func Slice[A expression.ArrayExpression, N expression.IntExpression](input A, position, n N) arrayOperator

Slice Returns a subset of an array. $slice has one of two syntax forms: The following syntax returns elements from either the start or end of the array: { $slice: [ <array>, <n> ] } The following syntax returns elements from the specified position in the array: { $slice: [ <array>, <position>, <n> ] }

func SortArray

func SortArray[A expression.ArrayExpression](input A, sortBy bsonx.Bson) arrayOperator

SortArray New in version 5.2. Sorts an array based on its elements. The sort order is user specified. $sortArray has the following syntax:

$sortArray: {
  input: <array>,
  sortBy: <sort spec>
}

func Zip

func Zip[A expression.ArrayExpression](inputs []A, useLongestLength bool, defaults []A) arrayOperator

Zip Transposes an array of input arrays so that the first element of the output array would be an array containing, the first element of the first input array, the first element of the second input array, etc. For example, $zip would transform [ [ 1, 2, 3 ], [ "a", "b", "c" ] ] into [ [ 1, "a" ], [ 2, "b" ], [ 3, "c" ] ]. $zip has the following syntax:

{
   $zip: {
       inputs: [ <array expression1>,  ... ],
       useLongestLength: <boolean>,
       defaults:  <array expression>
   }
}

Types

type IndexOfArrayOptions

type IndexOfArrayOptions struct {
	// contains filtered or unexported fields
}