Remove blank element from array

Question

When I'm saving multiple select from a ruby on rails form it appears to be adding a blank element at the front. How do I remove it? The field is selected_player.

{"utf8"=>"✓",
 "authenticity_token"=>"H8W7qPBezubyeU0adnTGZ4oJqYErin1QNz5oK0QV6WY=",
 "schedule"=>{"event"=>"1",
 "result_id"=>"",
 "time"=>"26/10/2012",
 "duration"=>"15",
 "arrival_time"=>"14",
 "location_id"=>"25",
 "selected_players"=>["", "38", "41"],
 "team_id"=>"1",
 "opponent_id"=>"7",
 "home_or_away"=>"Home"},
 "commit"=>"Save Event"}

controller

def update
  @schedule = Schedule.find(params[:id])
  @user = User.find(current_user)
  @players = User.where(:team_id => current_user[:team_id]).all

  respond_to do |format|
    if @schedule.update_attributes(params[:schedule])
      Notifier.event_added(@user,@schedule).deliver
      format.html { redirect_to(@schedule,
                                :notice => "#{event_display_c(@schedule.event)} vs #{@schedule.opponent.name} was successfully updated.") }
      format.json { head :no_content }
    else
      format.html { render :action => "edit" }
      format.json { render :json => @schedule.errors, :status => :unprocessable_entity }
    end
  end
end

Joris · Accepted Answer · 2013-12-23 15:24:26Z

20

This works for empty strings:

array.delete_if(&:empty?)

To filter out empty strings and nil values use:

array.delete_if(&:blank?)

Example:

>> a = ["A", "B", "", nil]
=> ["A", "B", "", nil]
>> a.delete_if(&:blank?)
=> ["A", "B"]

answered Dec 23, 2013 at 15:24

Joris

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1 Comment

Michael Taylor Over a year ago

This works perfectly and can easily be added to the model logic in a before save function.

Salil · Accepted Answer · 2012-10-24 14:49:02Z

7

Ref reject! of Array class

params["schedule"]["selected_players"] = ["", "38", "41"]
params["schedule"]["selected_players"].reject!{|a| a==""} #gives params["selected_players"] = ["38", "41"]

edited Oct 24, 2012 at 14:49

answered Oct 24, 2012 at 13:18

Salil

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3 Comments

Boss Nass Over a year ago

thats given me undefined method reject!' for nil:NilClass`

Salil Over a year ago

Please check my edited answer change params["selected_players"] to params["schedule"]["selected_players"]

aqwan Over a year ago

to avoid issues where the params may be incomplete you could add a try : params["schedule"]["selected_players"].try(:delete_if, &:blank?)

Eduardo Maia · Accepted Answer · 2013-11-21 17:14:16Z

2

This should work as well.

params["schedule"]["selected_players"].reject!(&:blank?)

answered Nov 21, 2013 at 17:14

Eduardo Maia

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Comments

thorsten müller · Accepted Answer · 2012-10-24 13:17:20Z

0

Something like:

params["selected_players"].select!{|val| !val.empty?}

should work

answered Oct 24, 2012 at 13:17

thorsten müller

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Comments

Yanhao · Accepted Answer · 2012-10-24 14:18:24Z

0

What is "selected_players"? Is it something like "collection_singular_ids" of the collection associations? If so, you can leave it as it is, because ActiveRecord will remove the blank elements from the array with following code:

ids = Array.wrap(ids).reject { |id| id.blank? }

answered Oct 24, 2012 at 14:18

Yanhao

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Comments

Scott Henderson · Accepted Answer · 2021-06-25 01:22:09Z

0

If you want to handle this in the model rather than the controller you can add a setter method like this

def selected_players=(param_array)
  write_attribute(:selected_players, param_array.reject(&:blank?))
end

answered Jun 25, 2021 at 1:22

Scott Henderson

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Comments

Benjamin Tan Wei Hao · Accepted Answer · 2012-10-24 14:53:56Z

-3

I think params["selected_players"].compact is the most succinct.

Docs are here: http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-compact

answered Oct 24, 2012 at 14:53

Benjamin Tan Wei Hao

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1 Comment

Wizard of Ogz Over a year ago

This will not work for empty strings like the OP wants.

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