freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-an.../intermediate-algorithm-scri.../search-and-replace.md

2.4 KiB

id title challengeType forumTopicId dashedName
a0b5010f579e69b815e7c5d6 搜索与替换 5 16045 search-and-replace

--description--

在这道题目中,我们需要写一个字符串的搜索与替换函数,它的返回值为完成替换后的新字符串。

这个函数接收的第一个参数为待替换的句子。

第二个参数为句中需要被替换的单词。

第三个参数为替换后的单词。

注意: 在更换原始单词时保留原始单词中第一个字符的大小写。 即如果传入的第二个参数为 Book,第三个参数为 dog,那么替换后的结果应为 Dog

--hints--

myReplace("Let us go to the store", "store", "mall") 应返回 Let us go to the mall

assert.deepEqual(
  myReplace('Let us go to the store', 'store', 'mall'),
  'Let us go to the mall'
);

myReplace("He is Sleeping on the couch", "Sleeping", "sitting") 应返回 He is Sitting on the couch

assert.deepEqual(
  myReplace('He is Sleeping on the couch', 'Sleeping', 'sitting'),
  'He is Sitting on the couch'
);

myReplace("I think we should look up there", "up", "Down") 应返回 I think we should look down there

assert.deepEqual(
  myReplace('I think we should look up there', 'up', 'Down'),
  'I think we should look down there'
);

myReplace("This has a spellngi error", "spellngi", "spelling") 应返回 This has a spelling error

assert.deepEqual(
  myReplace('This has a spellngi error', 'spellngi', 'spelling'),
  'This has a spelling error'
);

myReplace("His name is Tom", "Tom", "john") 应返回 His name is John

assert.deepEqual(
  myReplace('His name is Tom', 'Tom', 'john'),
  'His name is John'
);

myReplace("Let us get back to more Coding", "Coding", "algorithms") 应返回 Let us get back to more Algorithms

assert.deepEqual(
  myReplace('Let us get back to more Coding', 'Coding', 'algorithms'),
  'Let us get back to more Algorithms'
);

--seed--

--seed-contents--

function myReplace(str, before, after) {
  return str;
}

myReplace("A quick brown fox jumped over the lazy dog", "jumped", "leaped");

--solutions--

function myReplace(str, before, after) {
  if (before.charAt(0) === before.charAt(0).toUpperCase()) {
    after = after.charAt(0).toUpperCase() + after.substring(1);
  } else {
    after = after.charAt(0).toLowerCase() + after.substring(1);
  }
  return str.replace(before, after);
}