m = require("mathjs@11.8")
function isBooleanIndex(x) {
return isFlat(x) && m.getMatrixDataType(x) === "boolean";
}
function isFlat(x) {
if (m.isArray(x)) {
return m.size(x).length === 1;
} else if (m.isMatrix(x)) {
return x._size.length === 1;
} else {
return false;
}
}
function convertBooleanToIndex(X) {
const ind = [];
X.forEach((x, i) => {
if (x) ind.push(i);
});
return ind;
}
function convertBooleanToIndexMap (booleans) {
// convert an array of booleans to index
return booleans.map((_, i) => i).filter((_, i) => booleans[i])
}
convertBooleanToIndex([false])
convertBooleanToIndex([true, false, true, true, false, true])
convertBooleanToIndexMap([true, false, true, true, false, true])
isBooleanIndex([true, false, false])
m.index([1])
m.index([])
function isFlatArray(X){
X.forEach(x=>{
if(Array.isArray(x)) {
return false
}
})
return true
}
isFlatArray([1,2])
isFlatArray([[1],[2,2]])
m.matrix([true, false])
emptyIndex = m.index([])
notEmptyIndex = m.index([1])
m.index([1,2])
notEmptyIndex._dimensions.length
isEmptyIndex(m.index([1,2])) // should be false
isEmptyIndex(m.index([])) // shuld be true
isEmptyIndex(m.index([],[1])) // should be true
isEmptyIndex(m.index([],[1])) // should be true
isEmptyIndex(m.index(m.range(0,2),1))
function isEmptyIndex(index) {
for (let i = 0; i < index._dimensions.length; ++i) {
if (index._dimensions[i]._size[0] === 0){
return true
}
}
return false
}
m.index([],[1])._dimensions[0]._size[0] === 0
m.index(m.range(0,3),1)
isEmptyIndex(m.index(0)) // should be false
m.index([0,1])
m.help("index)
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
