当我上传文件并请求以下参数时：
params[:product][:images_attributes]["0"][:image]
它返回：
#<ActionDispatch::Http::UploadedFile:0x007fcbe5c8f768 @original_filename="motorized-bicycle-9.jpeg", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"product[images_attributes][0][image]\"; filename=\"motorized-bicycle-9.jpeg\"\r\nContent-Type: image/jpeg\r\n", @tempfile=#<File:/var/folders/qf/gjxv0pl142scx9131j0k65_00000gs/T/RackMultipart20140328-969-12np4s4>>
我要用来获取的红宝石代码是filename什么？
我在我的rails应用程序中有一个pdf文件,我想创建一个链接.当用户点击链接时我希望在浏览器中预览pdf,如果不可以,我希望它可以下载.我很确定如果它是pdf的下载链接,许多浏览器会默认预览,但我不确定.
我正在尝试获得所有产品的平均价格，其中一些是NULL。我想知道何时使用以下查询：
SELECT AVG(Price) AS PriceAverage FROM Products;
是否包含有NULL价格的产品，还是跳过它们？
我有以下表格行嵌入ruby:
<tr class=<%= "image-carousel-show thumb-#{index}" %>>
这创造了这个:
<tr class="image-carousel-show" thumb-0="">
但是,我希望thumb-0它在行的类中,而不是像它当前那样自己的属性.
这就是我希望它显示为:
<tr class="image-carousel-show thumb-0">
我不知道为什么会这样做,在ERB中我将它全部作为一个字符串所以我不知道为什么它被输出为两个.
我有以下数组:
[[1, 2], [44, 1], [18395, 3]]
我通过使用此代码获得的:
current_user.friends_products.where("units.primary_image_id IS NOT NULL").group_by{|u| u.creator_id}.map {|k,v| [k, v.length]}
我想按每个数组的第二个值从最大到最小排序数组.所以,这就是我想要实现的目标:
[[18395, 3], [1, 2], [44, 1]]
该循环应该取每本书的价格,将其加到总数中,然后将平均值放在每本书的页面上,直到用户输入"N"为止
<script type="text/javascript">
var ct = 1;
var yesORno = "Y";
while (yesORno = "Y"){
book = prompt("What is the price of book #" + ct, 0);
total = parseInt(book) + total;
ans = total / ct;
document.write("<p>With book #" + ct +" The average is " + ans + "</p>");
ct = ct + 1;
yesORno = prompt("Would you like to continue? (Y/N)", "")
}
</script>
这是我的代码.它应该采用两个字符串并逐个字符地比较它们的差异.
import java.util.Scanner;
public class Positions {
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
String first = scan.next();
String second = scan.next();
if(first.length()>second.length()){
int length = first.length();
}else{
int length = second.length();
}
for(int i=0; i<length; i++){
if(first.charAt(i)!=second.charAt(i)){
System.out.print(i+" "+first.charAt(i)+" "+second.charAt(i));
}
}
}
}
我尝试编译时收到此错误:
----jGRASP exec: javac -g Positions.java
Positions.java:12: error: cannot find symbol
for(int i=0; i < length; i++){
^
symbol: variable length
location: class Positions
1 error
----jGRASP wedge: exit code for process …我在下面有这个哈希叫disciplines:
disciplines = {"Architecture"=>"architecture", "Auditing"=>"auditing", "Consulting"=>"consulting", "Delivery"=>"delivery", "Development"=>"development", "Engineering"=>"engineering", "Environment / IT"=>"environment", "Graphic Design"=>"graphic_design", "Management"=>"management", "Requirements"=>"requirements", "Research"=>"research", "Support"=>"support", "System Design"=>"system_design", "Test & Eval"=>"test_and_evaluation", "Writing"=>"writing"}
我想将它转换为一个看起来像这样的哈希数组:
[{"name"=>"Architecture", "value"=>"architecture"}, {"name"=>"Auditing", "value"=>"auditing"}, {"name"=>"Consulting", "value"=>"consulting"}, {"name"=>"Delivery", "value"=>"delivery"}, {"name"=>"Development", "value"=>"development"}, {"name"=>"Engineering", "value"=>"engineering"}, {"name"=>"Environment / IT", "value"=>"environment"}, {"name"=>"Graphic Design", "value"=>"graphic_design"}, {"name"=>"Management", "value"=>"management"}, {"name"=>"Requirements", "value"=>"requirements"}, {"name"=>"Research", "value"=>"research"}, {"name"=>"Support", "value"=>"support"}, {"name"=>"System Design", "value"=>"system_design"}, {"name"=>"Test & Eval", "value"=>"test_and_evaluation"}, {"name"=>"Writing", "value"=>"writing"}]
所以我只想在第一个哈希中获取每个键值对并将其映射到一个新的哈希,其中键现在是一个值,name值现在是一个值value,并将它们全部放入哈希数组中