freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/regular-expressions/match-beginning-string-patterns.chinese.md

id, title, challengeType, forumTopicId, localeTitle

id	title	challengeType	forumTopicId	localeTitle
587d7db7367417b2b2512b9d	Match Beginning String Patterns	1	301349	匹配字符串的开头

Description

回顾一下之前的挑战，正则表达式可以用于查找多项匹配。还可以查询字符串中符合指定匹配模式的字符。 在之前的挑战中，使用字符集中的插入符号（^）来创建一个否定字符集，形如[^thingsThatWillNotBeMatched]。在字符集之外，插入符号用于字符串的开头搜寻匹配模式。

let firstString = "Ricky is first and can be found.";
let firstRegex = /^Ricky/;
firstRegex.test(firstString);
// Returns true
let notFirst = "You can't find Ricky now.";
firstRegex.test(notFirst);
// Returns false

Instructions

在正则表达式中使用^符号，以匹配仅在字符串rickyAndCal的开头出现的"Cal"。

Tests

tests:
  - text: "你的正则表达式应该搜寻有一个大写字母的<code>'Cal'</code>。"
    testString: assert(calRegex.source == "^Cal");
  - text: 你的正则表达式不应该使用任何标志。
    testString: assert(calRegex.flags == "");
  - text: "你的正则表达式应该匹配字符串开头的<code>'Cal'</code>。"
    testString: assert(calRegex.test("Cal and Ricky both like racing."));
  - text: "你的正则表达式不应该匹配字符串中间的<code>'Cal'</code>。"
    testString: assert(!calRegex.test("Ricky and Cal both like racing."));

Challenge Seed

let rickyAndCal = "Cal and Ricky both like racing.";
let calRegex = /change/; // Change this line
let result = calRegex.test(rickyAndCal);

Solution

let rickyAndCal = "Cal and Ricky both like racing.";
let calRegex = /^Cal/; // Change this line
let result = calRegex.test(rickyAndCal);