幸运的是,一项新的提案(截至2021年1月的第3阶段) (https://github.com/tc39/proposal-relative-indexing-method)将at()方法引入了数组(以及类型化数组和字符串),并解决了方括号的许多限制。 array.at() 方法 简而言之,array.at(index)用来访问处于index位置的元素。 如果index是一个正整数>= 0,则该方法返回...
// Create an array: var x = [ 1, 2, 3, 4 ]; // Define a list of indices for elements we want to retrieve from `x`: var y = [ 0, 2 ]; // Attempt to retrieve the desired elements: var v = x[ y ]; // => desired: [ 1, 3 ] // returns undefined is equivalent to...
console.log("array indexing:", obj.getLiteral()) return new IndexExpression(props) } initPrecedencesMap() { ... //change 14 this.precedencesMap[this.lexer.LEFT_BRACKET] = this.INDEX } 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 2...
幸运的是,一项新的提案(截至2021年1月的第3阶段) (https://github.com/tc39/proposal-relative-indexing-method)将 at() 方法引入了数组(以及类型化数组和字符串),并解决了方括号的许多限制。 array.at() 方法 简而言之,array.at(index) 用来访问处于 index 位置的元素。 如果index 是一个正整数 >= 0,...
You can create a multikey index on a field with an array value by calling the createIndex() method. The following code creates an ascending index on the cast field in the movies collection of the sample_mflix database: const database = client.db("sample_mflix"); const movies = database...
letlast=array.at(-1) 0x02 如果浏览器还不支持这个方法,可以Polyfill: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 functionat(n){// ToInteger() abstract opn=Math.trunc(n)||0;// Allow negative indexing from the endif(n<0)n+=this.length;// OOB access is guaranteed to return undefi...
array([1.5, 0]); x = np.random.randn([100, 2]).add(x); norm = x.pow(2).sum({axis: -1}).pow(0.5); x.divide_assign(norm.index(':', 'None')); for(let point2d of x){ console.log(point2d.tolist(), point2d.norm(), point2d.max()); if(np.all(point2d.equal(x....
stores({ friends: "id, name" // use binary UUID as id }); // IndexedDB 2.0 allows indexing ArrayBuffer and XXXArray // (typed arrays) (but not Blobs) async function playWithBinaryPrimKey() { // Store the binary data in indexedDB: await db.friends.put({ id: new Uint8Array([1,...
boost function(arr, str, int) => float A custom boost function used when indexing contents to the index. The function has this signature: Function(words[], term, index) => Float. It has 3 parameters where you get an array of all words, the current term and the current index where th...
在JS 里面有一个实验性语法 Array.prototype.at 方法 (Relative indexing method) ,接受一个整数作为下标返回对应的元素。如果传非负下标,那就和方括号语法一致,如果传负的下标,就会从后向前查找,可以很方便地访问数组最后一个元素: AI检测代码解析 const fruit = ["apple", "banana"]; ...