--- id: 56533eb9ac21ba0edf2244cd title: 访问嵌套数组 challengeType: 1 videoUrl: 'https://scrimba.com/c/cLeGDtZ' forumTopicId: 16160 dashedName: accessing-nested-arrays --- # --description-- 正如我们在前面的例子所见,对象可以嵌套对象和数组。与访问嵌套对象一样,用中括号操作符同样可以访问嵌套数组。 下面是如何访问嵌套数组的例子: ```js var ourPets = [ { animalType: "cat", names: [ "Meowzer", "Fluffy", "Kit-Cat" ] }, { animalType: "dog", names: [ "Spot", "Bowser", "Frankie" ] } ]; ourPets[0].names[1]; // "Fluffy" ourPets[1].names[0]; // "Spot" ``` # --instructions-- 使用点操作符和中括号操作符来检索变量`myPlants`的第二棵树。 # --hints-- `secondTree`应该等于 "pine"。 ```js assert(secondTree === 'pine'); ``` 使用点操作符和中括号操作符来检索变量`myPlants`。 ```js assert(/=\s*myPlants\[1\].list\[1\]/.test(code)); ``` # --seed-- ## --after-user-code-- ```js (function(x) { if(typeof x != 'undefined') { return "secondTree = " + x; } return "secondTree is undefined"; })(secondTree); ``` ## --seed-contents-- ```js // Setup var myPlants = [ { type: "flowers", list: [ "rose", "tulip", "dandelion" ] }, { type: "trees", list: [ "fir", "pine", "birch" ] } ]; // Only change code below this line var secondTree = ""; // Change this line ``` # --solutions-- ```js var myPlants = [ { type: "flowers", list: [ "rose", "tulip", "dandelion" ] }, { type: "trees", list: [ "fir", "pine", "birch" ] } ]; // Only change code below this line var secondTree = myPlants[1].list[1]; ```