结果在 rails 上用 ruby 重复了几次消息

Question

我有这个代码：

<% @lookup_coins.each do |x| %>
    <% if @symbol == '' %>
        <%= 'Sorry, but you forgot to write something, LOL'%>
    <% elsif @symbol == x %>
        <%= x["symbol"]%> <br/> <%= x["name"]%>: <%= number_to_currency(x['quote']['USD']['price'].round(2) , :unit => "$ ") %> <br/> <%= x["cmc_rank"]%> <br/> 
    <% else 'Sorry, there was a mistake, try again'%>
<% end %>

信息如下所示：

[{"id"=>1, "name"=>"Bitcoin", "symbol"=>"BTC", "slug"=>"bitcoin", "num_market_pairs"=>9713, "date_added"=>"2013-04-28T00:00:00.000Z", "tags"=>["mineable", "pow", "sha-256", "store-of-value", "state-channels", "coinbase-ventures-portfolio", "three-arrows-capital-portfolio", "polychain-capital-portfolio"], "max_supply"=>21000000, "circulating_supply"=>18633612, "total_supply"=>18633612, "platform"=>nil, "cmc_rank"=>1, "last_updated"=>"2021-02-20T07:45:02.000Z", "quote"=>{"USD"=>{"price"=>55541.51774356704, ...

我不确定如何以正确的方式做到这一点

Answer 1

您似乎无法匹配实际的 symbol 值，而是希望 @symbol 与哈希完美匹配，但事实并非如此。

其次，您还每次通过循环打印“忘记写东西”消息，这是错误的。您可以摆脱循环，只需使用 find 立即定位条目，作为奖励，您可以更轻松地检测到“遗漏”条件。

看看是否能找到匹配的条目，否则显示消息。

修复看起来像：

<%- if @symbol.blank? -%>
  Sorry, but you forgot to write something.
<%- else -%>
  <%- found = @lookup_coins.find { |c| c['symbol'] == @symbol } -%>
  <%- if (found) -%>
    <%= found["symbol"]%> <br/> <%= found["name"]%>:
    <%= number_to_currency(found['quote']['USD']['price'].round(2), :unit => "$ ") %>
    <br/>
     <%= found["cmc_rank"]%> <br/> 
  <%- else -%>
    Sorry, there was a mistake, try again
  <%- end -%>
<%- end -%>

在这里使用 @symbol.blank? 比 == '' 更宽容，因为它也会拒绝一堆空格 and/or 制表符。

提示：不要使用 <%= '...' %>，而是按原样将文本放在那里。默认是回显它。

Answer 2

<% if @symbol %>
<%@resultant_symbol = @lookup_coins['data'].select {|lookup_coin| lookup_coin["symbol"] == @symbol }%>
<%if @resultant_symbol.present?%>
   <% x = @resultant_symbol.first %>
   <%= x["symbol"]%> <br/> <%= x["name"]%>: <%= number_to_currency(x['quote']['USD']['price'].round(2) , :unit => "$ ") %> <br/> <%= x["cmc_rank"]%> <br/> 
<%else%>
   <%= @symbol = 'Sorry, there was a mistake, try again'%>
<%end%>

结果在 rails 上用 ruby 重复了几次消息

The result repeats the message several times with ruby on rails

ruby

ruby-on-rails

erb