Is there any difference between the use of double quotes to single quotes in Python?   "A string with double quotes" 'A string with single quotes'   Are they identical? Are there differences in how python interprets these strings?
According to the documentation, they're pretty much interchangeable.  Is there a stylistic reason to use one over the other?
What is the easiest way to strip a desktop edition to a server edition? We have installed Ubuntu desktop edition on our development server. Now that we have it in a data center we would like to strip it down to a server edition.  Is there an easy way of doing so rather than just going in and uninstalling packages by hand? Variation of Pythagorean triplets: $x^2+y^2 = z^3$ I need to prove that the equation $x^2 + y^2  = z^3$ has infinitely many solutions for positive $x, y$ and $z$. I got to as far as $4^3 = 8^2$ but that seems to be of no help.  Can some one help me with it? I want to install Skype, but I can't locate it in Software Center or by using Synaptic Package Manager. Can anyone help me? Possible Duplicate:          Is there anywhere or anyone to complain to about the behaviour of moderators? I've been "spoken" to offensively by a moderator, and I'm unhappy about it. I would like to achieve this effect using my Nikon P510:      Are there any suggestions or tips that would help me do that? How to stop creating .DS_Store on Mac? Why should I use the keyword "final" on a method parameter in Java? How do moving charges produce magnetic fields? function customization_form_user_register_form_alter(&amp;$form, &amp;$form_state, $form_id) {  $form['account']['pass']['#attributes']['placeholder'] = t('Password'); }   I am trying to set placeholder on password field in registration form.  I seted placeholder on username and email, but on password field won't work...  Any help? Thank you! I was wondering why binary crossentropy can be used as the loss function in autoencoders trained on (normalized) images, e.g.  or ? I know that binary crossentropy can be used in binray classification problems where the ground-truth labels (i.e. $y$) are either 0 or 1 and therefore when predictions (i.e. $p$) are correct, in both cases, the loss value would be zero:  $$ BCE(y,p) = -y.log(p) - (1-y).\log{(1-p)} $$  $$ BCE(0,0) = 0, BCE(1,1) = 0 $$  However, binary crossentropy does not have a value of zero when neither of its arguments are both zero or one, which is the case for an autoencoder with ground-truth labels in range $[0,1]$ (i.e. assuming the input data has been normalized in this range). I thought a regression loss function such as mean squared error or mean absolute error must be used instead, which have a value of zero when labels and predictions are the same. What am I missing here? How do I bake/add material colors onto my UVmap? I looked everywhere from tutorials to documents and either they only talk about texturing or they are doing the tutorial in 'blender render' when I need it in 'cycles render'.   I have a cube that is toon shaded red. And as you can see it is unwrapped to show the map.    Now I would like to add the color that's on the cube onto the map.   As you can see at the bottom of the image that I created a new image called 'untitled'. Now the next step of baking the colors onto the map is where I become lost. Regardless of which 'Bake Type' that I used, I keep getting error messages like: No valid selected objects.  Everything looks selected to me. No, I am not new to Blender but I am new to color baking. Thank you for any help provided; I used a simple cube first before using other models I already created. reason for exec in wrapper scripts I have seen wrapper script examples which in a nutshell are following:  #!/bin/bash  myprog=sleep echo "This is the wrapper script, it will exec "$myprog""  exec "$myprog" "$@"   As seen above, they use exec to replace the newly created shell almost immediately with the $myprog. One could achieve the same without exec:  #!/bin/bash  myprog=sleep echo "This is the wrapper script, it will exec "$myprog""  "$myprog" "$@"   In this last example, a new bash instance is started and then $myprog is started as a child process of the bash instance.  What are the benefits of the first approach? Prove that $V = V_1 \oplus V_2$ in the following Let $V$ be a vector space over $\mathbb{C}$ such that $T^2=1_V$. Define  $V_1 = \left\{v\in V |\ T(v) = v \right\}$,  $\ V_2 = \left\{v\in V |\ T(v) = -v\right\}$  prove that $V = V_1 \oplus V_2$  For start, I've shown that $V_1\ ,V2$ are subspace of $V$. However, I'm stuck trying to show that $\forall \ v\in V,\ v = v_1 + v_2$ where $v_1 \in V1, v_2 \in V_2$.  I know at some point I have to make use of  $T^2=1_V$, but cant figure out how. Any help or insight is deeply appreciated. Show that $A\in\mathbb{C}_n$ is normal $\iff$ $tr(A*A) = \sum_{i = 1}^n|\lambda_i|^2$, where $\lambda_1,...,\lambda_n$ are the eigenvalues of $A$. In a P.I.D., if $a^m = b^m$ and $a^n = b^n$ for $m, n \in \mathbb{N}$ with $\gcd(m,n) = 1$, then $a=b$ Let $R$ be a principal ideal domain, and $a, b \in R$ with $a^m = b^m$ and $a^n = b^n$ for $m, n \in \mathbb{N}$, and $\gcd(m, n) = 1$. I now want to show that we then already have $a = b$.   I think the statement is easily seen to be true if $a = 0$ (or $b = 0$), since if $a = 0$ and $a^m = b^m$, then $a = b$ since $R$ doesn't contain any nontrivial zero divisors, so $b ≠ 0$ already implicates $b^m = b \cdot b^{m-1} ≠ 0$.  I don't really know how to prove the statement for the general case, where I can't directly apply the fact that $R$ doesn't have any zero divisors except $0$. I most likely have to use the fact at some point that $gcd(a, b) = 1$, but I'm not sure how. Cannot open adobe reader on Ubuntu 12.10 64bits I downloaded AdbeRdr9.5.1-1_i386linux_enu.deb from the official website and installed it. Nothing wrong happened during the installation. But when I click Adobe Reader's icon, it has no response. Neither can I open a pdf file with Adobe Reader.  I checked that the package name is adobereader-enu:i386. Multiple Inheritance in C# I recently received an invitation to a conference and I'm trying to determine how reputable it is. Is there a good way to go about this? I'd like to be able to introspect a C++ class for its name, contents (i.e. members and their types) etc. I'm talking native C++ here, not managed C++, which has reflection. I realise C++ supplies some limited information using RTTI. Which additional libraries (or other techniques) could supply this information? Group algebra ever a field? Let $G$ be a group. Let $K$ be any field and consider its group algebra $K[G]$. It is known that if $G$ is a finite group then $K[G]$ is never a field. Or even if $G$ is not finite: if $G$ has at least one non-trivial torsion element, then $K[G]$ is not a field.  Question: Do there exist infinite groups $G$ such that $K[G]$ is a field or a division ring?