如何在數組字段中保存收到的字符串參數？

如何從字符串參數中提取並保存數組？我想轉換字符串beafore_create，但這不起作用。當我評論before_create：航點Mongoid拋出錯誤：如何在數組字段中保存收到的字符串參數？

Parameters: { 
    "utf8"=>"✓", 
    "authenticity_token"=>"nehoT1fnza/ZW4XB4v27uZsfFjjOu/ucIhzMmMKgWPo=", 
    "trip"=>{ 
     "title"=>"test", 
     "description"=>"test", 
     "waypoints"=>"[[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]" 
    } 
} 

Completed 500 Internal Server Error in 1ms 

Mongoid::Errors::InvalidType (Field was defined as a(n) Array, but received a String with the value "[[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]".):

編輯感謝您的幫助，現在它工作，但我不知道是不是下面的方法是很好的。我從航點waypoints_s和DEF航點刪除before_create和更改參數名稱變形點焊waypoints_s：

#Parameters: 
#"waypoints"=>"[[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]" 
"waypoints_s"=>"[[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]" 

class Trip 
    include Mongoid::Document 
    field :title, :type => String 
    field :description, :type => String 
    field :waypoints, :type => Array 

    #before_create :waypoints 

    #def waypoints=(arg) 
    def waypoints_s=(arg) 
    if (arg.is_a? Array) 
     #@waypoints = arg 
     self.waypoints = arg 
    elsif (arg.is_a? String) 
     #@waypoints = arg.split(',') 
     self.waypoints = JSON.parse(arg) 
    else 
     return false 
    end 
    end 
end 

class TripsController < ApplicationController 
    def create 
    @trip = Trip.create(params[:trip]) 
    @trip.save 
    end 
end

來源

2011-11-13 leon

分析字符串作爲JSON對象：

require 'json' 

waypoints = "[[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]" 
JSON.parse(waypoints) 

=> [[52.40637, 16.92517], [52.40601, 16.925040000000003], [52.405750000000005, 16.92493], [52.40514, 16.92463], [52.404320000000006, 16.924200000000003]]

來源

2011-11-13 13:17:49 vise

它在控制檯中運行良好，但在befor_create方法欄中忽略它並保存所有沒有航點的數據。 – leon

您需要使用連載http://api.rubyonrails.org/classes/ActiveRecord/Base.html#method-c-serialize

該方法通過YAML格式序列化的對象數據庫（假設只是具有某種格式的文本）。

class Trip < ActiveRecord::Base 

    serialize :waypoints 

end 

trip = Trip.create(:waypoints => [[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]) 

Trip.find(trip.id).waypoints # => [[52.40637,16.92517],[52.40601,16.925040000000003],[52.405750000000005,16.92493],[52.40514,16.92463],[52.404320000000006,16.924200000000003]]

來源

2011-11-13 12:22:44 megas

我發現，在Mongoid我可以存儲陣列的字段而不序列化。我的問題仍然存在，我認爲有些方法將路線點參數從字符串轉換爲數組或刪除引號？ – leon

serialize方法正在爲您進行轉換，您只是像使用通常的數組那樣使用航點。對於我來說，使用序列化是更簡潔的方式，然後使用例如json，因爲你不需要解析，轉換的東西。 – megas

如何在數組字段中保存收到的字符串參數？

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