Operators in the Flux language

Flux includes the following types of operators:

Arithmetic operators
Comparison operators
Logical operators
Assignment operators
Function operators
String Operators
Literal constructors
Miscellaneous operators

Also see:

Operator precedence

Arithmetic operators

Arithmetic operators take two numerical values (either literals or variables) and perform a calculation that returns a single numerical value.

Operator	Description	Example	Result
`+`	Addition	`1 + 1`	`2`
`-`	Subtraction	`3 - 2`	`1`
`*`	Multiplication	`2 * 3`	`6`
`/`	Division	`9 / 3`	`3`
`^`	Exponentiation	`2 ^ 3`	`8`
`%`	Modulo	`10 % 5`	`0`

In the current version of Flux, values used in arithmetic operations must be of the same numeric type (integer or float). Operations with values of different numeric types will result in a type error.

Comparison operators

Comparison operators compare expressions and return true or false based on the comparison.

Operator	Description	Example	Result
`==`	Equal to	`"abc" == "abc"`	`true`
`!=`	Not equal to	`"abc" != "def"`	`true`
`<`	Less than	`1 < 2`	`true`
`>`	Greater than	`1 > 2`	`false`
`<=`	Less than or equal	`1 <= 2`	`true`
`>=`	Greater than or equal	`1 >= 2`	`false`
`=~`	Equal to regular expression	`"abc" =~ /[a-z]*/`	`true`
`!~`	Not equal to regular expression	`"abc" !~ /[0-9]*/`	`true`

The > and < operators also compare the lexicographic order of strings.

Logical operators

Operator	Description
`not`	Returns `true` if right operand is `false`. Otherwise, returns `false`.
`exists`	Returns `false` if right operand is null. Otherwise, returns `true`.
`and`	Returns `true` if both operands are true. Otherwise, returns `false`.
`or`	Returns `true` if any operand is true. Otherwise, returns `false`.

Short-circuit evaluation

Flux logical operators observe the short-circuiting behavior seen in other programming languages. The evaluation of the left-hand (LH) operand determines if the right-hand (RH) operand is evaluated.

When the operator is and and the LH operand evaluates to false, the evaluation returns false without evaluating the RH operand.
When the operator is or and the LH operand evaluates to true, the evaluation returns true without evaluating the RH operand.

Assignment operators

An assignment operator assigns a value to its left operand based on the value of its right operand.

Operator	Description	Example	Meaning
`=`	Assign value of left expression to right expression	`x = y`	x = y

Function operators

Function operators facilitate the creation of functions and control the flow of data through operations.

Operator	Description	Examples	Meaning
`\|>`	Pipe‑forward	`data \|> function()`	Tables contained in the “data” variable are piped into the function.
`<-`	Pipe‑receive	`tables=<-`	The “tables” variable or parameter is assigned to data piped into the operation. This operator is used for any data type passed into a function; not just table data.
`=>`	Arrow	`(r) => r.tag1 == "tagvalue"`	The arrow passes a record or parameters into function operations.
`()`	Function call	`top(n:10)`	Call the `top` function setting the `n` parameter to `10` and perform the associated operations.

See Define custom functions for examples of function operators is use.

String Operators

String operators concatenate or compare string values.

Operator	Description	Examples	Result
`+`	Concatenation	`"ab" + "c"`	`"abc"`
`<`	Less than in lexicographic order	`"ant" < "bee"`	`true`
`>`	Greater than in lexicographic order	`"ant" > "bee"`	`false`

Literal constructors

Literal constructors define fixed values.

Operator	Description
`[ ]`	List / array
`{ }`	Record
`""`	String

Miscellaneous operators

Operator	Description	Example
`( )`	Logical grouping	`r._value / (r._value * 2)`
`,`	Sequence delimiter	`item1, item2, item3`
`:`	Key-value separator	`{name: "Bob"}`
`.`	Member access / dot reference	`r._measurement`

Operator precedence

The table below outlines operator precedence. Operators with a lower number have higher precedence.

Precedence	Operator	Description
1	`a()`	Function call
	`a[]`	Member or index access
	`.`	Member access
2	`\|>`	Pipe forward
3	`() => 1`	FunctionLiteral
4	`^`	Exponentiation
5	`*` `/` `%`	Multiplication, division, and modulo
6	`+` `-`	Addition and subtraction
7	`==` `!=`	Comparison operators
	`<` `<=`
	`>` `>=`
	`=~` `!~`
8	`not`	Unary logical operator
	`exists`	Null check operator
9	`and`	Logical AND
10	`or`	Logical OR
11	`if` `then` `else`	Conditional

Expressions Packages

operators

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