Rails error message when parsing a JSON response

Question

I have a method that gets artists top albums from Lastfm

    def get_albums
        @albums = Array.new
        @artistname.each do |name|
            s = LastFM::Artist.get_top_albums(:artist => name, :limit => 1)
            r = JSON.parse(s.to_json)['topalbums']['album']['name']
            @albums.push r                      
            end
    end

This method work fine and returns an array of albums for each artist as long as the artist has a top album, if they don't I get a NoMethodError undefined method `[]' for nil:NilClass.

What I'm trying to do is add a check when parsing to try and get pass this NoMethodError but can't seem to figure it out. I tried this:

    def get_albums
        @albums = Array.new
        @artistname.each do |name|
            s = LastFM::Artist.get_top_albums(:artist => name, :limit => 1)
            r = JSON.parse(s.to_json)['topalbums']['album']['name']
            if['topalbums']['album']['name'].empty?
                @albums.push(@artistname + "does not have a top album")
            else
                @albums.push r                      
            end
                end

    end

Which gives me a TypeError can't convert String into Integer message

Any ideas how I could fix this? Thanks

Justin Wood · Accepted Answer · 2014-02-28 19:03:57Z

0

The + operator is not a concat operator in ruby.

What you are attempting to use is the << operator.

@albums.push(@artistname << " does not have a top album")

answered Feb 28, 2014 at 19:03

Justin Wood

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7 Comments

user3333211 Over a year ago

Cheers I've changed the + to << but I'm still getting the TypeError cannot convert String to integer on this line of code if['topalbums']['album']['name'].empty?

Justin Wood Over a year ago

Are you actually getting the error on this line of code?

Justin Wood Over a year ago

Also, if['topalbums']['album']['name'].empty? doesn't make any sense. You need to specify the hash that you are searching through.

Justin Wood Over a year ago

Change that to if r.empty?

user3333211 Over a year ago

Tried that but getting undefined method `[]' for nil:NilClass for r = JSON.parse(s.to_json)['topalbums']['album']['name']

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