tilde

For example: unsigned int i = ~0; Result : Max number I can assign to i and signed int y = ~0; Result : -1 Why do I get -1 ? Shouldn't I get the maximum number that I can assign to y ? Both 4294967295 (a.k.a. UINT_MAX ) and -1 have the same binary representation of 0xFFFFFFFF or 32 bits all set to 1 . This is because signed numbers are represented using two's complement . A negative number has its MSB (most significant bit) set to 1 and its value determined by flipping the rest of the bits, adding 1 and multiplying by -1 . So if you have the MSB set to 1 and the rest of the bits also set to 1

I am trying to do the following rewrite of tilde URLs: RewriteRule ^/?~folder/(.*) http://whatever.com/$1 [R=302,L] I want any links with whatever.com/~folder/something to become whatever.com/something . It seems that the above rewrite rule works if my situation excluded the tilde (also tried escaping it, \~ ), but with the tilde it does not perform the rewrite. Is there a broader configuration setting I need to adjust to enable rewriting in my situation? I understand normally ~folder refers to a user's home directory, but I don't know how that comes into play or can be adjusted in my

1、熵的定义 熵最早是一个物理学概念，由克劳修斯于1854年提出，它是描述事物无序性的参数，跟热力学第二定律的宏观方向性有关：在不加外力的情况下，总是往混乱状态改变。熵增是宇宙的基本定律，自然的有序状态会自发的逐步变为混沌状态。 1948年，香农将熵的概念引申到信道通信的过程中，从而开创了”信息论“这门学科。香农用“信息熵”来描述随机变量的不确定程度，也即信息量的数学期望。 关于 信息熵、条件熵、联合熵、互信息、相对熵、交叉熵 请点击蓝字直达 2、最大熵模型 这里引用吴军博士《数学之美》中关于最大熵的论述 最大熵原理指出，当我们需要对一个随机事件的概率分布进行预测时，我们的预测应当满足全部已知的条件，而对未知的情况不要做任何主观假设。在这种情况下，概率分布最均匀，预测的风险最小。因为这时概率分布的信息熵最大，所以人们称这种模型叫“最大熵模型” 理解最大熵原理，最简单的例子就是掷色子，当我们对这个色子一无所知时，我们一般会假定它每面朝上的概率是均等的，即各点出现的概率均为 1/6。这就保留了最大的不确定性，也就是说让熵达到最大。当我们假定这个色子是韦小宝的，六点朝上的概率是 1/2，这样其他面朝上的概率是多少呢？在无其他信息情况下，其他面朝上的概率均为 1/10. 在满足已知条件前提下，如果没有更多的信息，则那些不确定部分都是“等可能的”。而等可能性通过熵最大化来刻画

For some reason, I cannot get this simple statement to work on the ñ . It seems to work on anything else but doesn't like that character. Any ideas? DF['NAME']=DF['NAME'].str.replace("ñ","n") Thanks I'm assuming you're using Python 2.x here and this is likely a Unicode problem. Don't worry, you're not alone--unicode is really tough in general and especially in Python 2, which is why it's been made standard in Python 3. If all you're concerned about is the ñ , you should decode in UTF-8, and then just replace the one character. That would look something like the following: DF['name'] = DF['name

I have this weird situation on my Mac running OSX Lion where the ~ (tilda) does not go to my user directory. Instead when I type "cd ˜", I get: -bash: cd: ˜: No such file or directory Any advice on how to fix this? Rômulo Jales Try this one: ˜ + <spacebar> It's results the tilde you want: ~ The ˜ character's code is 0x02DC and the code that works in bash like shortcut to home directory is 0x07E . Venkat Ganesh After changing the keyboard (System Preferences>Keyboard>Input Sources) from 'US International - PC' to 'U.S.', I was able to verify tilde sign (~) works as expected from Terminal. It