如何在.each_with_index中調用索引

Question

不確定這是行不通的。理想化

>> params[:payments][:"1"] 
    {":amount_paid"=>"100.00", ":date_paid"=>"5/8/2008"} 

但如果我寫這個..

>> params[:payments].each_with_index{|item, idx| item[:"#{idx}"]} 
TypeError Exception: Symbol as array index 

，我要做到這一點：

>> params[:payments] 
{"0"=>{":amount_paid"=>"80.00", ":date_paid"=>"2/27/2008"}, "1"=>{":amount_paid"=>"100.00", ":date_paid"=>"5/8/2008"}} 

這樣我就可以調用特定的對象與此

params[:payments].each_with_index do |item, idx|  
    @calc.payments[idx][:date_paid] = item[:"#{idx}"][":amount_paid"] 
    @calc.payments[idx][:amount_paid] = (item[:"#{idx}"][":amount_paid"]).to_f 
end 

更新：

基於一些答案，I'ved試過這樣：

params[:payments].each{|k,v| @calc.payments[k.to_i] = v[":amounts_paid"]} 

這原來@calc.payments到：

nil 
nil 

備份雖然，其他人似乎工作..

>> params[:payments].each{|k,v| p v[":amount_paid"]} 
"80.00" 
"100.00" 

而這一個..

>> params[:payments].each{|k,v| p @calc.payments[k.to_i]} 
{:date_awarded=>"1/2/2008", :judgement_balance=>1955.96} 
nil 

如何在循環中訪問item[idx]？

Answer 1

params[:payments].each do |k,v| 
    puts "Item %d amount=%s date=%s\n" % [k, v[":amount_paid"], v[":date_paid"]] 
end 
Item 0 amount=80.00 date=2/27/2008 
Item 1 amount=100.00 date=5/8/2008 

更新：

好，好，這裏是一個完整的程序..腳本..你可以實際運行。 由於您試圖理解Ruby，我認爲您應該在Rails之外使用它幾分鐘。無論如何，我嘲笑了@calc.payments。這段代碼將運行，顯然做你想要的。

require 'pp' 
(params = {})[:payments] = {"0"=>{":amount_paid"=>"80.00", ":date_paid"=>"2/27/2008"}, "1"=>{":amount_paid"=>"100.00", ":date_paid"=>"5/8/2008"}} 
pp params 
class T; attr_accessor :payments; end 
(@calc = T.new).payments = [] 
params[:payments].each do |k,v| 
    i = k.to_i 
    @calc.payments[i] ||= {} 
    @calc.payments[i][:date_paid] = v[":date_paid"] 
    @calc.payments[i][:amount_paid] = v[":date_paid"].to_f 
end 
pp @calc.payments 

如果你運行它，你應該看到：

{:payments=> 
    {"0"=>{":amount_paid"=>"80.00", ":date_paid"=>"2/27/2008"}, 
    "1"=>{":amount_paid"=>"100.00", ":date_paid"=>"5/8/2008"}}} 
[{:date_paid=>"2/27/2008", :amount_paid=>2.0}, 
{:date_paid=>"5/8/2008", :amount_paid=>5.0}] 

Answer 2

你可以做一個這樣的訪問值。由於params[:payments]包含一個散列，因此對於每次傳遞，key將被分配「0」，「1」等，並且value將被分配散列amount_paid和date_paid。

params[:payments].each do |key, value| 
    amount_paid = value[":amount_paid"] 
    ... 
end