# Expr

class
**Expr** (View source)

Fluent interface for building aggregation pipelines.

## Methods

Evaluates an array as a set and returns true if no element in the array is false. Otherwise, returns false. An empty array returns true.

Evaluates an array as a set and returns true if any of the elements are true and false otherwise. An empty array returns false.

Concatenates arrays to return the concatenated array.

Converts an expression object into an array, recursing into nested items

Converts a date object to a string according to a user-specified format.

Returns the day of the month for a date as a number between 1 and 31.

Returns a new expression object

Set the current field for building the expression.

No description

Evaluates an expression and returns the value of the expression if the expression evaluates to a non-null value. If the expression evaluates to a null value, including instances of undefined values or missing fields, returns the value of the replacement expression.

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.

Searches a string for an occurrence of a substring and returns the UTF-8 byte index (zero-based) of the first occurrence. If the substring is not found, returns -1.

Searches a string for an occurrence of a substring and returns the UTF-8 code point index (zero-based) of the first occurrence. If the substring is not found, returns -1.

Returns the weekday number in ISO 8601 format, ranging from 1 (for Monday) to 7 (for Sunday).

Returns the millisecond portion of a date as an integer between 0 and 999.

Accepts an array expression as an argument and returns an array with the elements in reverse order.

Takes two sets and returns an array containing the elements that only exist in the first set.

Takes two or more arrays and returns an array that contains the elements that appear in every input array.

Takes two arrays and returns true when the first array is a subset of the second, including when the first array equals the second array, and false otherwise.

Calculates the sample standard deviation of the input values.

Performs case-insensitive comparison of two strings. Returns 1 if first string is “greater than” the second string.

Returns the substring of a string.

Evaluates a series of case expressions. When it finds an expression which evaluates to true, $switch executes a specified expression and breaks out of the control flow.

## Details

###
at line 45
```
```**__construct**(DocumentManager $dm, ClassMetadata $class)

**__construct**(DocumentManager $dm, ClassMetadata $class)

###
at line 61
```
```**abs**(mixed|Expr $number)

**abs**(mixed|Expr $number)

Returns the absolute value of a number.

The

###
at line 79
```
```**add**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**add**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Adds numbers together or adds numbers and a date. If one of the arguments is a date, $add treats the other arguments as milliseconds to add to the date.

The arguments can be any valid expression as long as they resolve to either all numbers or to numbers and a date.

###
at line 91
```
```**addAnd**(array|Expr $expression, array|Expr ...$expressions)

**addAnd**(array|Expr $expression, array|Expr ...$expressions)

Adds one or more $and clauses to the current expression.

###
at line 109
```
```**addOr**(array|Expr $expression, array|Expr ...$expressions)

**addOr**(array|Expr $expression, array|Expr ...$expressions)

Adds one or more $or clause to the current expression.

###
at line 130
```
```**addToSet**(mixed|Expr $expression)

**addToSet**(mixed|Expr $expression)

Returns an array of all unique values that results from applying an expression to each document in a group of documents that share the same group by key. Order of the elements in the output array is unspecified.

AddToSet is an accumulator operation only available in the group stage.

###
at line 144
```
```**allElementsTrue**(mixed|Expr $expression)

**allElementsTrue**(mixed|Expr $expression)

Evaluates an array as a set and returns true if no element in the array is false. Otherwise, returns false. An empty array returns true.

The expression must resolve to an array.

###
at line 158
```
```**anyElementTrue**(array|Expr $expression)

**anyElementTrue**(array|Expr $expression)

Evaluates an array as a set and returns true if any of the elements are true and false otherwise. An empty array returns false.

The expression must resolve to an array.

###
at line 176
```
```**arrayElemAt**(mixed|Expr $array, mixed|Expr $index)

**arrayElemAt**(mixed|Expr $array, mixed|Expr $index)

Returns the element at the specified array index.

The

###
at line 189
```
```**avg**(mixed|Expr $expression)

**avg**(mixed|Expr $expression)

Returns the average value of the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key. Ignores nun-numeric values.

###
at line 204
```
```**case**(mixed|Expr $expression)

**case**(mixed|Expr $expression)

Adds a case statement for a branch of the $switch operator.

Requires {@link switch()} to be called first. The argument can be any valid expression that resolves to a boolean. If the result is not a boolean, it is coerced to a boolean value.

###
at line 223
```
```**ceil**(mixed|Expr $number)

**ceil**(mixed|Expr $number)

Returns the smallest integer greater than or equal to the specified number.

The

###
at line 238
```
```**cmp**(mixed|Expr $expression1, mixed|Expr $expression2)

**cmp**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: -1 if the first value is less than the second.

1 if the first value is greater than the second. 0 if the two values are equivalent.

###
at line 255
```
```**concat**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**concat**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Concatenates strings and returns the concatenated string.

The arguments can be any valid expression as long as they resolve to strings. If the argument resolves to a value of null or refers to a field that is missing, $concat returns null.

###
at line 272
```
```**concatArrays**(mixed|Expr $array1, mixed|Expr $array2, mixed|Expr ...$arrays)

**concatArrays**(mixed|Expr $array1, mixed|Expr $array2, mixed|Expr ...$arrays)

Concatenates arrays to return the concatenated array.

The

###
at line 288
```
```**cond**(mixed|Expr $if, mixed|Expr $then, mixed|Expr $else)

**cond**(mixed|Expr $if, mixed|Expr $then, mixed|Expr $else)

Evaluates a boolean expression to return one of the two specified return expressions.

The arguments can be any valid expression.

###
at line 304
```
static string|array
```**convertExpression**(mixed|Expr $expression)

**convertExpression**(mixed|Expr $expression)

Converts an expression object into an array, recursing into nested items

For expression objects, it calls getExpression on the expression object. For arrays, it recursively calls itself for each array item. Other values are returned directly.

###
at line 325
```
```**dateToString**(string $format, $expression)

**dateToString**(string $format, $expression)

Converts a date object to a string according to a user-specified format.

The format string can be any string literal, containing 0 or more format specifiers. The date argument can be any expression as long as it resolves to a date.

###
at line 338
```
```**dayOfMonth**(mixed|Expr $expression)

**dayOfMonth**(mixed|Expr $expression)

Returns the day of the month for a date as a number between 1 and 31.

The argument can be any expression as long as it resolves to a date.

###
at line 352
```
```**dayOfWeek**(mixed|Expr $expression)

**dayOfWeek**(mixed|Expr $expression)

Returns the day of the week for a date as a number between 1 (Sunday) and 7 (Saturday).

The argument can be any expression as long as it resolves to a date.

###
at line 365
```
```**dayOfYear**(mixed|Expr $expression)

**dayOfYear**(mixed|Expr $expression)

Returns the day of the year for a date as a number between 1 and 366.

The argument can be any expression as long as it resolves to a date.

###
at line 382
```
```**default**(mixed|Expr $expression)

**default**(mixed|Expr $expression)

Adds a default statement for the current $switch operator.

Requires {@link switch()} to be called first. The argument can be any valid expression.

Note: if no default is specified and no branch evaluates to true, the $switch operator throws an error.

###
at line 405
```
```**divide**(mixed|Expr $expression1, mixed|Expr $expression2)

**divide**(mixed|Expr $expression1, mixed|Expr $expression2)

Divides one number by another and returns the result. The first argument is divided by the second argument.

The arguments can be any valid expression as long as the resolve to numbers.

###
at line 417
```
```**eq**(mixed|Expr $expression1, mixed|Expr $expression2)

**eq**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns whether the are equivalent.

###
at line 432
```
```**exp**(mixed|Expr $exponent)

**exp**(mixed|Expr $exponent)

Raises Euler’s number to the specified exponent and returns the result.

The

###
at line 440
```
```**expr**()

**expr**()

Returns a new expression object

###
at line 462
```
```**field**(string $fieldName)

**field**(string $fieldName)

Set the current field for building the expression.

###
at line 482
```
```**filter**(mixed|Expr $input, mixed|Expr $as, mixed|Expr $cond)

**filter**(mixed|Expr $input, mixed|Expr $as, mixed|Expr $cond)

Selects a subset of the 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.

###
at line 495
```
```**first**(mixed|Expr $expression)

**first**(mixed|Expr $expression)

Returns the value that results from applying an expression to the first document in a group of documents that share the same group by key. Only meaningful when documents are in a defined order.

###
at line 510
```
```**floor**(mixed|Expr $number)

**floor**(mixed|Expr $number)

Returns the largest integer less than or equal to the specified number.

The

###
at line 515
```
```**getExpression**()

**getExpression**()

###
at line 530
```
```**gt**(mixed|Expr $expression1, mixed|Expr $expression2)

**gt**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: true when the first value is greater than the second value.

false when the first value is less than or equivalent to the second value.

###
at line 545
```
```**gte**(mixed|Expr $expression1, mixed|Expr $expression2)

**gte**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: true when the first value is greater than or equivalent to the second value.

false when the first value is less than the second value.

###
at line 558
```
```**hour**(mixed|Expr $expression)

**hour**(mixed|Expr $expression)

Returns the hour portion of a date as a number between 0 and 23.

The argument can be any expression as long as it resolves to a date.

###
at line 575
```
```**ifNull**(mixed|Expr $expression, mixed|Expr $replacementExpression)

**ifNull**(mixed|Expr $expression, mixed|Expr $replacementExpression)

Evaluates an expression and returns the value of the expression if the expression evaluates to a non-null value. If the expression evaluates to a null value, including instances of undefined values or missing fields, returns the value of the replacement expression.

The arguments can be any valid expression.

###
at line 590
```
```**in**(mixed|Expr $expression, mixed|Expr $arrayExpression)

**in**(mixed|Expr $expression, mixed|Expr $arrayExpression)

Returns a boolean indicating whether a specified value is in an array.

Unlike the $in query operator, the aggregation $in operator does not support matching by regular expressions.

###
at line 606
```
```**indexOfArray**(mixed|Expr $arrayExpression, mixed|Expr $searchExpression, mixed|Expr $start = null, mixed|Expr $end = null)

**indexOfArray**(mixed|Expr $arrayExpression, mixed|Expr $searchExpression, mixed|Expr $start = null, mixed|Expr $end = null)

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.

###
at line 632
```
```**indexOfBytes**(mixed|Expr $stringExpression, mixed|Expr $substringExpression, string|int|null $start = null, string|int|null $end = null)

**indexOfBytes**(mixed|Expr $stringExpression, mixed|Expr $substringExpression, string|int|null $start = null, string|int|null $end = null)

Searches a string for an occurrence of a substring and returns the UTF-8 byte index (zero-based) of the first occurrence. If the substring is not found, returns -1.

###
at line 658
```
```**indexOfCP**(mixed|Expr $stringExpression, mixed|Expr $substringExpression, string|int|null $start = null, string|int|null $end = null)

**indexOfCP**(mixed|Expr $stringExpression, mixed|Expr $substringExpression, string|int|null $start = null, string|int|null $end = null)

Searches a string for an occurrence of a substring and returns the UTF-8 code point index (zero-based) of the first occurrence. If the substring is not found, returns -1.

###
at line 681
```
```**isArray**(mixed|Expr $expression)

**isArray**(mixed|Expr $expression)

Determines if the operand is an array. Returns a boolean.

The

###
at line 695
```
```**isoDayOfWeek**(mixed|Expr $expression)

**isoDayOfWeek**(mixed|Expr $expression)

Returns the weekday number in ISO 8601 format, ranging from 1 (for Monday) to 7 (for Sunday).

The argument can be any expression as long as it resolves to a date.

###
at line 711
```
```**isoWeek**(mixed|Expr $expression)

**isoWeek**(mixed|Expr $expression)

Returns the week number in ISO 8601 format, ranging from 1 to 53.

Week numbers start at 1 with the week (Monday through Sunday) that contains the year’s first Thursday.

The argument can be any expression as long as it resolves to a date.

###
at line 727
```
```**isoWeekYear**(mixed|Expr $expression)

**isoWeekYear**(mixed|Expr $expression)

Returns the year number in ISO 8601 format.

The year starts with the Monday of week 1 (ISO 8601) and ends with the Sunday of the last week (ISO 8601).

The argument can be any expression as long as it resolves to a date.

###
at line 740
```
```**last**(mixed|Expr $expression)

**last**(mixed|Expr $expression)

Returns the value that results from applying an expression to the last document in a group of documents that share the same group by a field.

Only meaningful when documents are in a defined order.

###
at line 753
```
```**let**(mixed|Expr $vars, mixed|Expr $in)

**let**(mixed|Expr $vars, mixed|Expr $in)

Binds variables for use in the specified expression, and returns the result of the expression.

###
at line 765
```
```**literal**(mixed|Expr $value)

**literal**(mixed|Expr $value)

Returns a value without parsing. Use for values that the aggregation pipeline may interpret as an expression.

###
at line 781
```
```**ln**(mixed|Expr $number)

**ln**(mixed|Expr $number)

Calculates the natural logarithm ln (i.e loge) of a number and returns the result as a double.

The

###
at line 800
```
```**log**(mixed|Expr $number, mixed|Expr $base)

**log**(mixed|Expr $number, mixed|Expr $base)

Calculates the log of a number in the specified base and returns the result as a double.

The

###
at line 815
```
```**log10**(mixed|Expr $number)

**log10**(mixed|Expr $number)

Calculates the log base 10 of a number and returns the result as a double.

The

###
at line 830
```
```**lt**(mixed|Expr $expression1, mixed|Expr $expression2)

**lt**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: true when the first value is less than the second value.

false when the first value is greater than or equivalent to the second value.

###
at line 844
```
```**lte**(mixed|Expr $expression1, mixed|Expr $expression2)

**lte**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: true when the first value is less than or equivalent to the second value.

false when the first value is greater than the second value.

###
at line 858
```
```**map**(mixed|Expr $input, string $as, mixed|Expr $in)

**map**(mixed|Expr $input, string $as, mixed|Expr $in)

Applies an expression to each item in an array and returns an array with the applied results.

###
at line 870
```
```**max**(mixed|Expr $expression)

**max**(mixed|Expr $expression)

Returns the highest value that results from applying an expression to each document in a group of documents that share the same group by key.

###
at line 881
```
```**meta**(mixed|Expr $metaDataKeyword)

**meta**(mixed|Expr $metaDataKeyword)

Returns the metadata associated with a document in a pipeline operations.

###
at line 894
```
```**millisecond**(mixed|Expr $expression)

**millisecond**(mixed|Expr $expression)

Returns the millisecond portion of a date as an integer between 0 and 999.

The argument can be any expression as long as it resolves to a date.

###
at line 906
```
```**min**(mixed|Expr $expression)

**min**(mixed|Expr $expression)

Returns the lowest value that results from applying an expression to each document in a group of documents that share the same group by key.

###
at line 919
```
```**minute**(mixed|Expr $expression)

**minute**(mixed|Expr $expression)

Returns the minute portion of a date as a number between 0 and 59.

The argument can be any expression as long as it resolves to a date.

###
at line 934
```
```**mod**(mixed|Expr $expression1, mixed|Expr $expression2)

**mod**(mixed|Expr $expression1, mixed|Expr $expression2)

Divides one number by another and returns the remainder. The first argument is divided by the second argument.

The arguments can be any valid expression as long as they resolve to numbers.

###
at line 947
```
```**month**(mixed|Expr $expression)

**month**(mixed|Expr $expression)

Returns the month of a date as a number between 1 and 12.

The argument can be any expression as long as it resolves to a date.

###
at line 962
```
```**multiply**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**multiply**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Multiplies numbers together and returns the result.

The arguments can be any valid expression as long as they resolve to numbers.

###
at line 976
```
```**ne**(mixed|Expr $expression1, mixed|Expr $expression2)

**ne**(mixed|Expr $expression1, mixed|Expr $expression2)

Compares two values and returns: true when the values are not equivalent.

false when the values are equivalent.

###
at line 1005
```
```**pow**(mixed|Expr $number, mixed|Expr $exponent)

**pow**(mixed|Expr $number, mixed|Expr $exponent)

Raises a number to the specified exponent and returns the result.

The

###
at line 1017
```
```**push**(mixed|Expr $expression)

**push**(mixed|Expr $expression)

Returns an array of all values that result from applying an expression to each document in a group of documents that share the same group by key.

###
at line 1032
```
```**range**(mixed|Expr $start, mixed|Expr $end, mixed|Expr $step = 1)

**range**(mixed|Expr $start, mixed|Expr $end, mixed|Expr $step = 1)

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.

###
at line 1046
```
```**reduce**(mixed|Expr $input, mixed|Expr $initialValue, mixed|Expr $in)

**reduce**(mixed|Expr $input, mixed|Expr $initialValue, mixed|Expr $in)

Applies an expression to each element in an array and combines them into a single value.

###
at line 1058
```
```**reverseArray**(mixed|Expr $expression)

**reverseArray**(mixed|Expr $expression)

Accepts an array expression as an argument and returns an array with the elements in reverse order.

###
at line 1072
```
```**second**(mixed|Expr $expression)

**second**(mixed|Expr $expression)

Returns the second portion of a date as a number between 0 and 59, but can be 60 to account for leap seconds.

The argument can be any expression as long as it resolves to a date.

###
at line 1087
```
```**setDifference**(mixed|Expr $expression1, mixed|Expr $expression2)

**setDifference**(mixed|Expr $expression1, mixed|Expr $expression2)

Takes two sets and returns an array containing the elements that only exist in the first set.

The arguments can be any valid expression as long as they each resolve to an array.

###
at line 1103
```
```**setEquals**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**setEquals**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Compares two or more arrays and returns true if they have the same distinct elements and false otherwise.

The arguments can be any valid expression as long as they each resolve to an array.

###
at line 1119
```
```**setIntersection**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**setIntersection**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Takes two or more arrays and returns an array that contains the elements that appear in every input array.

The arguments can be any valid expression as long as they each resolve to an array.

###
at line 1134
```
```**setIsSubset**(mixed|Expr $expression1, mixed|Expr $expression2)

**setIsSubset**(mixed|Expr $expression1, mixed|Expr $expression2)

Takes two arrays and returns true when the first array is a subset of the second, including when the first array equals the second array, and false otherwise.

The arguments can be any valid expression as long as they each resolve to an array.

###
at line 1150
```
```**setUnion**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

**setUnion**(mixed|Expr $expression1, mixed|Expr $expression2, mixed|Expr ...$expressions)

Takes two or more arrays and returns an array containing the elements that appear in any input array.

The arguments can be any valid expression as long as they each resolve to an array.

###
at line 1163
```
```**size**(mixed|Expr $expression)

**size**(mixed|Expr $expression)

Counts and returns the total the number of items in an array.

The argument can be any expression as long as it resolves to an array.

###
at line 1177
```
```**slice**(mixed|Expr $array, mixed|Expr $n, mixed|Expr|null $position = null)

**slice**(mixed|Expr $array, mixed|Expr $n, mixed|Expr|null $position = null)

Returns a subset of an array.

###
at line 1198
```
```**split**(mixed|Expr $string, mixed|Expr $delimiter)

**split**(mixed|Expr $string, mixed|Expr $delimiter)

Divides a string into an array of substrings based on a delimiter.

$split removes the delimiter and returns the resulting substrings as elements of an array. If the delimiter is not found in the string, $split returns the original string as the only element of an array.

###
at line 1213
```
```**sqrt**(mixed|Expr $expression)

**sqrt**(mixed|Expr $expression)

Calculates the square root of a positive number and returns the result as a double.

The argument can be any valid expression as long as it resolves to a non-negative number.

###
at line 1228
```
```**stdDevPop**(mixed|Expr $expression1, mixed|Expr ...$expressions)

**stdDevPop**(mixed|Expr $expression1, mixed|Expr ...$expressions)

Calculates the population standard deviation of the input values.

The arguments can be any expression as long as it resolves to an array.

###
at line 1245
```
```**stdDevSamp**(mixed|Expr $expression1, mixed|Expr ...$expressions)

**stdDevSamp**(mixed|Expr $expression1, mixed|Expr ...$expressions)

Calculates the sample standard deviation of the input values.

The arguments can be any expression as long as it resolves to an array.

###
at line 1264
```
```**strcasecmp**(mixed|Expr $expression1, mixed|Expr $expression2)

**strcasecmp**(mixed|Expr $expression1, mixed|Expr $expression2)

Performs case-insensitive comparison of two strings. Returns 1 if first string is “greater than” the second string.

0 if the two strings are equal. -1 if the first string is “less than” the second string.

The arguments can be any valid expression as long as they resolve to strings.

###
at line 1276
```
```**strLenBytes**(mixed|Expr $string)

**strLenBytes**(mixed|Expr $string)

Returns the number of UTF-8 encoded bytes in the specified string.

###
at line 1288
```
```**strLenCP**(mixed|Expr $string)

**strLenCP**(mixed|Expr $string)

Returns the number of UTF-8 code points in the specified string.

###
at line 1304
```
```**substr**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $length)

**substr**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $length)

Returns a substring of a string, starting at a specified index position and including the specified number of characters. The index is zero-based.

The arguments can be any valid expression as long as long as the first argument resolves to a string, and the second and third arguments resolve to integers.

###
at line 1322
```
```**substrBytes**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $count)

**substrBytes**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $count)

Returns the substring of a string.

The substring starts with the character at the specified UTF-8 byte index (zero-based) in the string and continues for the number of bytes specified.

###
at line 1340
```
```**substrCP**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $count)

**substrCP**(mixed|Expr $string, mixed|Expr $start, mixed|Expr $count)

Returns the substring of a string.

The substring starts with the character at the specified UTF-8 code point (CP) index (zero-based) in the string for the number of code points specified.

###
at line 1355
```
```**subtract**(mixed|Expr $expression1, mixed|Expr $expression2)

**subtract**(mixed|Expr $expression1, mixed|Expr $expression2)

Subtracts two numbers to return the difference. The second argument is subtracted from the first argument.

The arguments can be any valid expression as long as they resolve to numbers and/or dates.

###
at line 1368
```
```**sum**(mixed|Expr $expression)

**sum**(mixed|Expr $expression)

Calculates and returns the sum of all the numeric values that result from applying a specified expression to each document in a group of documents that share the same group by key. Ignores nun-numeric values.

###
at line 1381
```
```**toLower**(mixed|Expr $expression)

**toLower**(mixed|Expr $expression)

Converts a string to lowercase, returning the result.

The argument can be any expression as long as it resolves to a string.

###
at line 1394
```
```**toUpper**(mixed|Expr $expression)

**toUpper**(mixed|Expr $expression)

Converts a string to uppercase, returning the result.

The argument can be any expression as long as it resolves to a string.

###
at line 1409
```
```**trunc**(mixed|Expr $number)

**trunc**(mixed|Expr $number)

Truncates a number to its integer.

The

###
at line 1423
```
```**type**(mixed|Expr $expression)

**type**(mixed|Expr $expression)

Returns a string that specifies the BSON type of the argument.

The argument can be any valid expression.

###
at line 1436
```
```**week**(mixed|Expr $expression)

**week**(mixed|Expr $expression)

Returns the week of the year for a date as a number between 0 and 53.

The argument can be any expression as long as it resolves to a date.

###
at line 1449
```
```**year**(mixed|Expr $expression)

**year**(mixed|Expr $expression)

Returns the year portion of a date.

The argument can be any expression as long as it resolves to a date.

###
at line 1464
```
```**zip**(mixed|Expr $inputs, bool|null $useLongestLength = null, mixed|Expr|null $defaults = null)

**zip**(mixed|Expr $inputs, bool|null $useLongestLength = null, mixed|Expr|null $defaults = null)

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.

###
at line 1557
```
```**switch**()

**switch**()

Evaluates a series of case expressions. When it finds an expression which evaluates to true, $switch executes a specified expression and breaks out of the control flow.

To add statements, use the {@link case()}, {@link then()} and {@link default()} methods.