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Resize image proportionally with MaxHeight and MaxWidth constraints
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What's the difference between a proc and a lambda in Ruby?
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An example:
p = Proc.new {|a, b| puts a**2+b**2 } # => #<Proc:0x3c7d28@(irb):1>
p.call 1, 2 # => 5
p.call 1 # => NoMethodError: undefined method `**' for nil:NilClass
p.call 1, 2, 3 # => 5
l = lambda {|a, b| puts a**2+b**2 } # => #<Proc:0x15016c@(irb):5 (lambda)>
l.ca...
Does Ruby regular expression have a not match operator like “!~” in Perl?
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Select every Nth element in CSS
...;/h1>
<div>1</div> <div>2</div>
<div>3</div> <div>4</div>
<h2></h2>
<div>5</div> <div>6</div>
<div>7</div> <div>8</div>
<h2></h2>
<div>9</div> <...
What is tail recursion?
...ple function that adds the first N natural numbers. (e.g. sum(5) = 1 + 2 + 3 + 4 + 5 = 15).
Here is a simple JavaScript implementation that uses recursion:
function recsum(x) {
if (x === 1) {
return x;
} else {
return x + recsum(x - 1);
}
}
If you called recsum(5), th...
linux 下巧妙使用squid代理服务器 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...点。
1．共享网络
2．加快访问速度，节约通信带宽
3．防止内部主机受到攻击
4．限制用户访问，完善网络管理
原理：
① 客户端A向代理服务器提出访问Internet的请求。
② 代理服务器接受到请求后，首先与访问控制列...
Move all files except one
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143
If you use bash and have the extglob shell option set (which is usually the case):
mv ~/Linux/O...
What exactly is Java EE?
... maintain. Spring was then a much better alternative to EJB2. But since EJB3 (Java EE 5), the EJB API was much improved based on lessons learnt from Spring. Since CDI (Java EE 6), there's not really a reason to look at again another framework like Spring to make the developers more easy as to develo...
Failed to instantiate module [$injector:unpr] Unknown provider: $routeProvider
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