Shekhar Prasad Rajak

Thanks @cyrillefr , please go ahead open a PR with few corner test cases. Love to see the changes in new release :)

If no one is working on it then I am interested to try to work on it.

I think `join` must work `on` the index as default, right ?

It took me time to understand the `core/merge.rb`, since there is no examples/docs added in file. 1. I see that `merge` is defined in `dataframe.rb` with no `option`. But as...

Actually my [above comment](https://github.com/SciRuby/daru/issues/234#issuecomment-289201378) is not much related to this issue, but I think that if 'joining on index' is fixed then using `inner` join (default join for `merge`) `merge`...

Thanks @thomasnaude for pointing it out this issue. I think, to resolve this issue one has to look into, why sorting is done in binary operation of vectors [here ](https://github.com/SciRuby/daru/blob/master/lib/daru/maths/arithmetic/vector.rb#L94).

Sorry for late response. That's great @cyrillefr ,PR is welcome.

I didn't understand this syntax `df.where(df_mask) = -1000` I think `df.where(df_mask)` must return : ``` Daru::DataFrame.new({ a: [1,NaN,NaN,4,NaN], b: [NaN,NaN,200,1,NaN] }) ``` And then we must have some method to...

Do we need to change [these kinds of comment syntax](https://github.com/SciRuby/daru/blob/master/lib/daru/dataframe.rb#L222) to YARD ?

`daru` uses Nyaplot, Gruff plotting libraries. `daru-view` uses Nyaplot (same as `daru` but it is able to generate html code) , HighCharts, GoogleCharts for plotting. So if we want to...