`<extractMathOperator>`

Returns the top-level operator of a math expression as text (e.g. "+", "vector")

<extractMathOperator> returns the top-level operator of a math expression as a text value. For a sum it returns "+", for a product "*", for an equation "=", for a vector "vector", and so on. If the expression is a single value (number, variable, or constant) with no top-level operator, the result is the empty string.

Unlike <extractMath>, which pulls out operands or function names and returns them as math expressions, <extractMathOperator> returns the operator itself as plain text — useful for branching on the kind of expression you have.

Attributes and Properties

Attributes for `<extractMathOperator>`

Positioning (2)

anchor

point. Default value: $\left( 0, 0 \right)$. Coordinates of the anchor point used to position this component on a graph.

positionFromAnchor

keyword. Where this component sits relative to its anchor point.

Value	Description
`upperRight`	Place the component above and to the right of the anchor point.
`upperLeft`	Place the component above and to the left of the anchor point.
`lowerRight`	Place the component below and to the right of the anchor point.
`lowerLeft`	Place the component below and to the left of the anchor point.
`top`	Place the component directly above the anchor point.
`bottom`	Place the component directly below the anchor point.
`left`	Place the component directly to the left of the anchor point.
`right`	Place the component directly to the right of the anchor point.
`center` (default)	Center the component on the anchor point.

Other (3)

draggable

boolean. Default value: true. Whether the text can be dragged on a graph.

isLatex

boolean. Default value: false. Whether the text content is treated as LaTeX.

layer

number. Default value: 0. Z-order layer index when shown on a graph.

Common to all components (9)

copy

reference. Create an independent copy of another component by reference. Enter a references a $name.

disabled

boolean. Default value: false. Whether this component is disabled and cannot be interacted with.

extend

reference. Extend another component by reference, inheriting its children and attributes. Enter a reference as $name.

fixed

boolean. Default value: false. Whether this component's value is fixed and cannot be modified.

fixLocation

boolean. Default value: false. Whether this component's location is fixed (preventing it from being moved while still allowing other modifications).

hide

boolean. Default value: false. Whether to hide this component from the rendered output.

isResponse

boolean. Default value: false. Whether this component is treated as a response for the purposes of assessment.

name

text. The name used to reference this component from elsewhere in the document.

styleNumber

integer. Default value: 1. The style number used to select this component's visual styling from the available style definitions.

Properties for `<extractMathOperator name="e">`

Positioning (2)

$e.anchor

point. The coordinates where this component is anchored on the graph.

$e.positionFromAnchor

text. Where this component sits relative to its anchor point.

Other (20)

$e.backgroundColor

text. Human-readable name for this component's background color, derived from the active style and theme.

$e.characters

[ text ]. The text value split into characters (graphemes).

$e.disabled

boolean. Whether this component is disabled and cannot be interacted with.

$e.draggable

boolean. Whether the text can be dragged on a graph.

$e.fixed

boolean. Whether this component's value is fixed and cannot be modified.

$e.fixLocation

boolean. Whether this component's location is fixed (preventing it from being moved while still allowing other modifications).

$e.hidden

boolean. Whether this component is hidden from the rendered output.

$e.isLatex

boolean. Whether the text content is treated as LaTeX.

$e.layer

number. Z-order layer index when shown on a graph.

$e.list

[ text ]. The text value split into items at commas.

$e.math

math. The text parsed as a math expression.

$e.number

number. The text parsed as a number.

$e.numCharacters

integer. The number of characters (graphemes) in the text value.

$e.numListItems

integer. The number of comma-separated items when the text is interpreted as a list.

$e.numWords

integer. The number of words in the text value.

$e.text

text. The text rendered as a plain text string.

$e.textColor

text. Human-readable name for this component's text color, derived from the active style and theme.

$e.textStyleDescription

text. Human-readable description of this component's text styling (color and any background color).

$e.value

text. The text result of applying this operator to its child math values.

$e.words

[ text ]. The text value split into words.

Common to all components (4)

$e.doenetML

text. The DoenetML source code that produced this component.

$e.hide

boolean. Whether to hide this component from the rendered output.

$e.isResponse

boolean. Whether this component is treated as a response for the purposes of assessment.

$e.styleNumber

integer. The style number used to select this component's visual styling from the available style definitions.

Examples

Example: Operator of a sum, product, and equation

For each expression the top-level operator (+, *, or =) is returned as text. The result of <extractMathOperator> is a regular <text> value, so it can be compared, displayed, or used in a condition.

Example: Operator from a `<mathInput>`

The operator updates live as the learner edits the input — try entering a vector (1,2,3), a function call f(x), a power x^2, or just a single number to see how the operator changes.

Example: Branch on the kind of expression

Comparing the result of <extractMathOperator> against string literals lets <conditionalContent> show different content for different kinds of expressions.

extractMath feedback

<extractMathOperator>