小编Jef*_*eff的帖子

我试图有条件地建立一个模型列表.即

@items = []

if some_condition
    @items << MyModel.where(...)
end

if another_condition
    @items << MyModel.where(...)
end

...

这不起作用.它实际上会构建一个正确对象的数组,但是当我访问数组中项目的字段和关系时,它们"找不到".我尝试了一些其他的东西像@items = MyModel.none和@items = {}和.merge,但没有工作.我似乎无法弄清楚这一点.

有条件地建立像这样的集合的最佳方法是什么？

更新我希望能够维护,Relation以便我可以继续查询它.where,.first以及其余的Relation方法.

我正在尝试使用rgba颜色的RaphaelJS创建渐变填充.换句话说,我希望起点和终点都具有一定程度的透明度.例如,20%黑色至0%黑色.这是怎么做到的？

这个小提琴就是我希望如何实现这一点,但正如你所看到的,底部的黑色是完全不透明的.http://jsfiddle.net/4aPj2/

r.circle(50,50,50).attr({fill:'90-rgba(0,0,0,0)-rgba(0,0,0,0.2)',opacity:0})

我有两个非常大的二进制字符串,如下所示.如何在这些大字符串上执行按位xor并以二进制形式显示结果？

字符串1. 100011010011000000001011101100101110111111101110101111101000111110110100011000010100010000101010111101000100011111101001110010010011111100110110100010000000011000101000011010100000110100001011001111000001100100101110111101111001010100100010110001001010110000011111011111010001001011101001110001100100011101100101100000011011101111010000001000000111111111110111100101101011010100011010100101000001101001110110011111011111110101010000111011111011011011100111001000011000011011111100101001110001111110001000000101000100110010111011011010100100111000001010110000101111000010110001011100010010110100010111111001000110011100111100111010100111110001110010110111010000010101000111110110110101010101000111110100010010000000110010000010101100101100101100100100110011000101101100000010100010101010011101101110101101111011010010101011001001000001011100011010101100111100110110101101101110000011010101101111

字符串2. 110001010111000100111011101010101010001011010111111000101010101111100100010111010000010100010110111111010000111110000101111000010010111000111110100000000011011100011100011101100010000101101010000000010011100101111011101001111110100100000010110001011000110100100111000001010001101111101101110111100011001101111100101101001110101111111100000010000111011111111111110101101101000000001110110101000100001101000011010000010001010101010001101000101011101011100110000110001000101011000100110111110110101110100001010111010101010011110011001101100010001000001110100111101111000011011101010010000011100000011011100101000101011101001000101100100101010100111010111010010100000010010110111000110011000101011111101110010110010100000110001100111001111101110001101011110001000001010101010110101111011011001101101011101111001010001111101000011101110100001100000001111110111100101010100011101110000011101100100010000010000000100101010110000010011000011110000001010111110110010100101000011001110110010001110000001111011110000011110011110101010010010001000000000010100001100110110001010110010110000100001011000100011110111100111110

我有点理解.eq()函数在jquery中是如何工作的,

<ul>
<li>item 2</li>
<li>item 4</li>
<li>item adf</li>
<li>item f</li>
</ul>

$('ul').find('li').eq(3); //this gives item f

但是,如果我想点击项目adf,我该怎么得到2的警报呢？

$('ul li').click(function(){
alert('//getting eq value'); //and then when clicked, it should say 2
});

谢谢

.Net 4.5安装到目录

C:\ WINDOWS\Microsoft.NET \框架\ v4.0.30319

Visual Studio 2010将.Net 4.0安装到目录中

C:\ Program Files(x86)\ Reference Assemblies\Microsoft\Framework.NETFramework\v4.0

即使在VS 2010之前安装了.Net 4.5.现在,无论我做什么,VS 2010和VS 11都会继续引用程序集.

C:\ Program Files(x86)\ Reference Assemblies\Microsoft\Framework.NETFramework\v4.0

即使我从项目中删除程序集,并通过浏览到4.5目录添加程序集

C:\ WINDOWS\Microsoft.NET \框架\ v4.0.30319

如何让Visual Studio引用此处的.Net程序集

C:\ Windows\Microsoft.NET\Framework\v4.0.30319 ??

谢谢