问题
I have this query
= f.select(:city, Country.where(:country_code => "es").collect(&:cities) {|p| [ p.city, p.id ] }, {:include_blank => 'Choose your city'})
Problem is I'm getting the following error
SyntaxError: (irb):26: both block arg and actual block given
From what I see I'm doing something wrong by including the collect(&:cities) and then declaring the block. Is there a way I can accomplish both with same query?
回答1:
Country.where(:country_code => "es").collect(&:cities)
is exactly the same as
Country.where(:country_code => "es").collect {|country| country.cities}
And this is why you are getting your error: you pass two blocks to the collect method. What you actually meant was probably something like this:
Country.where(:country_code => "es").collect(&:cities).flatten.collect {|p| [ p.city, p.id ] }
That will retrieve the countries, get the list of cities for each country, flattens the array to that you only have a one-dimensional one and the returns your array for the select.
As there is probably only one country per country code, you can also write it that way:
Country.where(:country_code => "es").first.cities.collect {|p| [ p.city, p.id ] }
来源：https://stackoverflow.com/questions/10288180/syntaxerror-irb26-both-block-arg-and-actual-block-given