In my list "A" i have got numbers and ' ', so I want to make a list of list named e.g "b", every list should have nine number (if it possible), no matter how much it have ' '. Any idea how to do this?  A = ['1', '3', '4', '5', '7', '8', '9', ' ', '13', '16', '3', ' ', '5', '17'] B = [ ['1', '3, '4', '5', '7', '8', '9', ' ', '13', '16'], ['3', ' ', '5', '17'] ]
I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:
Visiting Greece with back-to-back Schengen visas (One from Germany, other from Italy) I have a Schengen Visa issued by Germany, which expire on 11th Jan 2014, and I can remain in the zone till 11th Jan 23.59 PM. I have already visited Germany in the past with this visa, so I can travel whenever in Schengen zone directly from my country (Turkey).  I have a second Schengen Visa issued by Italy, which START on 12th Jan 2014, such that I can remain in Schengen zone from 12th Jan 00.00 AM onwards (I'm putting times to clarify which dates are inclusive).  I would like to travel to Greece with this visa: Entering the country on 6th January, and leaving the country on 19th January.  Is this allowed? Or do I have to leave the country first, and then re-enter through Italy? I am interested in how uncertainty can be accounted for when considering the risk of extinction of a species. Forgive me for extending a rather tired thought experiment, but at least it's familiar territory and I hope it illustrates what I am trying to understand.  Let's say that Schrödinger was not satisfied with killing and not killing only one cat, so he went out and collected the last 15 remaining Himalayan Snow-Cats. He put each one in a box with a vial of poison, hammer, and a trigger device for releasing the hammer. Each trigger device has a known probability of releasing the hammer within any given hour, and the poison will take 5 hours to kill a cat (things got a bit trippy when he used radioactive decay, so this time he steers clear of quantum mechanics). After one hour, Schrödinger receives a notice from the ethics board telling him he's nuts and ordering him to release the cats immediately. He pushes a button which opens a cat-flap at the back of each box, thus releasing them all back into the wild. By the time the humane society check the boxes, all the cats have bolted. Before anyone can restrain him, Schrödinger detonates the remaining triggers, so nobody knows how many of the cats were poisoned.  The probability that each of the cats is poisoned is as follows:   0.17 0.46 0.62 0.08 0.40 0.76 0.03 0.47 0.53 0.32 0.21 0.85 0.31 0.38 0.69   After 5 hours have elapsed and all poisoned cats have died, what is the probability that there are:   (A) More than 10 Himalayan Snow-Cats still alive  (B) 10 or less still alive (C) 5 or less still alive (D) 2 or less still alive Why does performance of a regular hard drive decrease over the duration of a benchmark while SSD doesn't? I use HD Tune to measure performance of the hard drive.  The tests typically take 2-3 minutes and the transfer rate of a regular hard drive decreases dramatically as the test comes to a close.    However, the SSD drive performance stays the same over (pic below) the life of the test.  This happens on all my computers.  Why is that? I'm a web designer and I'd like to make a custom wordpress theme for my upcoming blog. The template is already made in photoshop but I need a good starting point. I don't have too much experience with Wordpress but I want something that is SEO friendly which I can edit without risking getting poor search results.  I Know about Starkers and that there are other blank themes out there, but are they good for SEO? Using the Well Ordering Principle to Show that n^3 - n is divisible by 6. I read the following two sources and I think I understand the structure of proofs involving WOP, but I am stuck on the open-ended part where you prove P(n-1) for the  following problem:    Use the well-ordering principle to show that n^3 - n is divisible by 6.    Any help would be greatly appreciated!   Note: After factoring out (n-1)^3 - (n-1) it took the form of n^3 - 3n^2 + 2n and the only difference between that and n^3 - n is "3n^2 - 3n" which I proved was divisible by 6 via induction. Is there a better way to solve this problem?  Edit: , post is useful however I not supposed to use induction for the main part of the proof. How can I change this method to query my master detail object? I am new to Apex trying to do some practice assignments and have gotten stuck on this junction object query.  Task: Edit the current getUser() method to do the following:  Return a custom object (that you define in the class) with the current getUser method's query data, and the list of teams the person belongs to (by querying the team assignments).   Parent Object 1: User (Standard Object) Parent Object 2: Team (Custom Object) Junction Object: Team Assignments (Custom Object)    **Original Class &amp; getUser Method** global class CTI {     global class CTIException extends Exception {}      global static User getUser() {          return [SELECT Id, Name, ProfileId, Profile.Name, UserRoleId, UserRole.Name, Username                  FROM User WHERE Id = :UserInfo.getUserId() ];     } } Is there PvP in Diablo 3? How does it work? This is frustrating for me. The UV-textures to vertex cols add-on doesn't seem to work despite the specific instructions. Any other tutorials I can find are either very old or very poor.  I'd like to know how to do this in Blender 2.79. I need vertex colors in my ambient occlusion for use in Shader Forge. I have a group $G$ with $p^2$ elements, where $p$ is a prime number. Some (potentially) useful preliminary information I have is that there are exactly $p+1$ subgroups with $p$ elements, and with that I was able to show $G$ has a normal subgroup $N$ with $p$ elements.   My problem is showing that $G$ is abelian, and I would be glad if someone could show me how.   I had two potential approaches in mind and I would prefer if one of these were used (especially the second one).   First: The center $Z(G)$ is a normal subgroup of $G$ so by Langrange's theorem, if $Z(G)$ has anything other than the identity, it's size is either $p$ or $p^2$. If $p^2$ then $Z(G)=G$ and we are done. If $Z(G)=p$ then the quotient group of $G$ factored out by $Z(G)$ has $p$ elements, so it is cylic and I can prove from there that this implies $G$ is abelian. So can we show theres something other than the identity in the center of $G$?  Second: I list out the elements of some other subgroup $H$ with $p$ elements such that the intersection of $H$ and $N$ is only the identity (if any more, due to prime order the intersected elements would generate the entire subgroups). Let $N$ be generated by $a$ and $H$ be generated by $b$. We can show $NK= G$, i.e every element in G can be wrriten like $a^k b^l $. So for this method, we just need to show $ab=ba$ (remember, these are not general elements in the set, but the generators of $N$ and $H$).   Do any of these methods seem viable? I understand one can give very strong theorems using Sylow theorems and related facts, but I am looking for an elementary solution (no Sylow theorems, facts about p-groups, centrailzers) but definitions of centres and normalizers is fine. How long is it safe to drink coffee after brewed? I was readng Wikipedia article (English one) about radiation pressure because there is something I still cannot figure out. As I understand it, radiation pressure emerges from conservation of momentum. Photons or electromagnetic waves possess momentum and when they are absorbed, reflected or even emitted, the aborber/reflector/emitter experiences a pressure that is proportional to the irradiance (in watts per square meter). OK. In the case of a perfect reflector that does nothing but reflecting incoming radiation, it would seem the reflector is pushed and the radiation is reflected in opposite directions. But the radiation has not lost anything, it has only changed direction. And I do not understand how something can be set in motion (the reflector), which amounts to do work, yet the source of this work does not lose energy. I mean, if the radiation, after a U turn, meets a second reflector, it would have pushed two reflectors a way, yet it would continue in its original direction as if nothing happened...? What am I missing here? Should not photons lose something? l, ls & la -- what are the differences, and are there more of these commands? How to evaluate these two integrals. What features differ between the Xbox 360 and PC versions of Minecraft? What differences does the Xbox 360 version of Minecraft have compared to playing on the PC? To clarify - I'm concerned more about the differences exclusive to each platform, not just differences of features that will probably be added in future updates (for example, crafting). Otherwise, I feel this question could be compared to &quot;What is the difference between Minecraft version x and version y&quot;, which isn't what I'm asking. if p is prime then 1920 divides $p^4-10p^2+9$ I added this to /etc/crontab on a few different linux &amp; freebsd systems:  # monthly reboot: 3rd Tuesday of every month 56 07 15-21 * 2 root /sbin/shutdown -r now   I want a reboot on the 3rd TUESDAY of every month.  However, all the systems rebooted on the 3rd Wednesday of this month (the 19th).  What am I doing wrong?  Update: Thanks to Ranon's answer below, looks like the below revision will work, can anyone confirm or is there an even better way of doing it?  # monthly reboot: 3rd Tuesday of every month 56 07 15-21 * * root test $(date +\%u) -eq 2 &amp;&amp; /sbin/shutdown -r now Converting a list of tuples into a dict I have a list of tuples like this:  [ ('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('c', 1), ]   I want to iterate through this keying by the first item, so, for example, I could print something like this:  a 1 2 3 b 1 2 c 1   How would I go about doing this without keeping an item to track whether the first item is the same as I loop around the tuples? This feels rather messy (plus I have to sort the list to start with)... Should the site prompt new users to include an @name in comments? Neat series convergence result This is a nice problem on series convergence that I recently stumbled upon. Given a non-negative sequence of real numbers $(a_n)$ such that $$\sum_{n=1}^\infty a_n &lt; \infty,$$ show that there exists a non-decreasing sequence of non-negative numbers $b_n$ such that $$b_n \to \infty \quad\text{ and } \quad \sum_{n=1}^\infty a_n b_n &lt; \infty.$$ In other words, for every convergent series with non-negative terms, there is another convergent series with "substantially larger" terms.  I have a solution (see below), but maybe someone else has a different, simpler, and/or more elegant solution. Twice now I've tried pan frying fillets of white fish (Swai and Flouder) in olive oil and butter.  Both times the fish has disintegrated into unsightly mush.  Is there some technique I'm missing?  How can I pan fry without the fish falling apart?