Iterate through array using Map and Select method Together in Ruby

Question

I am developing an application where I'm stuck with the following code.

I have an array of links which is holding some links posted by a user in a form. say for example my array is bunch1 = ["google.com","http://yahoo.com"]

Now, before I store them into database I need to make sure that each link has "http://" added at the beginning because I have 'validate:' logic in my ActiveRecord object.

So my logic is that I will iterate through the array and check if "http://" string segment present before each link in the array. So clearly I have to add "http://" string segment before "google.com" in my array.

So I have written a code like this:

bunch2=bunch1.map { |y| y="http://"+y }

But it creates a bunch2 array like bunch2=["http://google.com","http://http://yahoo.com"]

As you can see it adds an extra "http://" before "http://yahoo.com" .

To solve this problem I modified the above code like this:

bunch2 = bunch1.select { |x|  x !~ /http/ }.map { |y| y="http://"+y }

but it's generating a array like bunch2 = ["http://google.com"] because the regular expression with select method is eliminating the yahoo.com

Can somebody please give me solution for this problem. Thanks in advance...

Ron Warholic · Accepted Answer · 2013-01-04 17:24:02Z

5

Why not test in the call to map?

bunch2 = bunch1.map {|y| y !~ /^http/ ? "http://#{y}" : y }

edited Jan 4, 2013 at 17:24

answered Jan 3, 2013 at 16:19

Ron Warholic

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Siddharth Over a year ago

I copied your code and ran that. But it's giving me an error saying: syntax error, unexpected '='. So I changed it to "=~" rather than "~=".But this time again it's crating the same array with "http://yahoo.com"...that again adding an extra "http://" before the element.

Siddharth · Accepted Answer · 2013-01-04 08:33:51Z

0

Ok, guys I have found the solution to this problem. So the code don't need a select method at all. It just needs a ternary operator for this. So my one liner code goes like this:-

@[email protected] { |x| x.match(/http:/) ? x : "http://"+x }

The above code using the match method for matching with regular expression. If it finds a match then the element is unchanged otherwise the "httP://" string is added at the beginning.

answered Jan 4, 2013 at 8:33

Siddharth

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