見習村11 - Extract the domain name from a URL

11 - Extract the domain name from a URL

Don’t say so much, just coding…

Instruction

Write a function that when given a URL as a string, parses out just the domain name and returns it as a string. For example:

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domain_name("http://github.com/carbonfive/raygun") == "github" 
domain_name("http://www.zombie-bites.com") == "zombie-bites"
domain_name("https://www.cnet.com") == "cnet"

Ruby

Init

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def domain_name(url)
  # return just the domain name
end

Sample Testing

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Test.assert_equals(domain_name("http://google.com"), "google")
Test.assert_equals(domain_name("http://google.co.jp"), "google")
Test.assert_equals(domain_name("www.xakep.ru"), "xakep")
Test.assert_equals(domain_name("https://youtube.com"), "youtube")

Javascript

Init

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function domainName(url){
  //your code here
}

Sample Testing

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Test.assertEquals(domainName("http://google.com"), "google");
Test.assertEquals(domainName("http://google.co.jp"), "google");
Test.assertEquals(domainName("www.xakep.ru"), "xakep");
Test.assertEquals(domainName("https://youtube.com"), "youtube");

Thinking

想法(1): 原本其實是從 URI 的方式寫完的，不過發現要處理的東西有點多，後來覺得 start_with 來解決就可以，也不用 regex 去 metch 所有條件（regex 就爛）
想法(2): 用 gsub 把所有要篩選的條件寫進來也不錯

https://ithelp.ithome.com.tw/upload/images/20200926/20120826iQVDzANvdd.jpg
圖片來源：Unsplash Marvin Meyer

Hint & Reference

Solution

Ruby

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# Solution 1
def domain_name(url)
  url = url.start_with?('www.') ? url.split('www.').last : url.split('//').last
  url.split('.').first
end

# Solution 2
def domain_name(url)
  url.start_with?('www.') ? url.split('www.').last.split('.').first
                          : url.split('//').last.split('.').first
end

# Solution 3
def domain_name(url)
  url.gsub('http://', '')
     .gsub('https://', '')
     .gsub('www.', '')
     .split(".")[0]
end

Javascript

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// Solution 1 gsub to replace XDDD
function domainName(url){
  return url.replace('http://', '')
            .replace('https://', '')
            .replace('www.', '')
            .split('.')[0];
}