freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/basic-javascript/manipulate-arrays-with-shift.chinese.md

id, title, challengeType, videoUrl, forumTopicId, localeTitle

id	title	challengeType	videoUrl	forumTopicId	localeTitle
56bbb991ad1ed5201cd392cd	Manipulate Arrays With shift()	1	https://scrimba.com/c/cRbVETW	18238	使用 shift() 操作数组

Description

pop()函数用来移出数组中最后一个元素。如果想要移出第一个元素要怎么办呢？ 这就是.shift()的用武之地。它的工作原理就像.pop()，但它移除的是第一个元素，而不是最后一个。

Instructions

使用.shift()函数移出myArray中的第一项，并把“移出”的值赋给removedFromMyArray。

Tests

tests:
  - text: <code>myArray</code>应该等于<code>[["dog", 3]]</code>。
    testString: assert((function(d){if(d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined){return true;}else{return false;}})(myArray));
  - text: <code>removedFromMyArray</code>应该包含<code>["John", 23]</code>。
    testString: assert((function(d){if(d[0] == 'John' && d[1] === 23 && typeof removedFromMyArray === 'object'){return true;}else{return false;}})(removedFromMyArray));

Challenge Seed

// Example
var ourArray = ["Stimpson", "J", ["cat"]];
var removedFromOurArray = ourArray.shift();
// removedFromOurArray now equals "Stimpson" and ourArray now equals ["J", ["cat"]].

// Setup
var myArray = [["John", 23], ["dog", 3]];

// Only change code below this line.
var removedFromMyArray;

After Test

(function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);

Solution

var myArray = [["John", 23], ["dog", 3]];

// Only change code below this line.
var removedFromMyArray = myArray.shift();