Say I have a list   my_input_list = [22,33,56,1]   and from a variable target_len I want to make (exclusive, sorted) sublists of that length  target_len = 2 #my_output_list_not_sorted = [[22,33][22,56][22,1][33,56][33,1][56,1]] my_output_list = [[22,33][22,56][1,22][33,56][1,33][1,56]]   or   target_len = 3 #my_output_list_not_sorted = [[[22,33,56][22,33,1][33,56,1]] my_output_list = [[22,33,56][1,22,33][1,33,56]]   Is there a neat way to do this?  I'm OK to sort my_input_list first if needed.  Thanks!
I have a list with 15 numbers in, and I need to write some code that produces all 32,768 combinations of those numbers.   I've found  (by Googling) that apparently does what I'm looking for, but I found the code fairly opaque and am wary of using it. Plus I have a feeling there must be a more elegant solution.  The only thing that occurs to me would be to just loop through the decimal integers 1–32768 and convert those to binary, and use the binary representation as a filter to pick out the appropriate numbers.   Does anyone know of a better way? Using map(), maybe?
I want to be able to ask a question by sending an email to some special email address for Stack Overflow. I have found this convenient in other situations like Google Groups, blogging, and Facebook walls, and it seems that technically it shouldn't be too hard to do.  Does this feature exist already? I'm kind of afraid to ask for features as some of them get downvoted simply since users think they are not neccessary (and not because the post is bad). What antivirus program can I use on Ubuntu? Are there any antivirus applications that work on Ubuntu 16.04? Thanks! Often I need two (or more) map frames in map layout to present different data next to each other. It is easy to make multiple map frames in QGIS Print Composer. BUT...  It is in the nature of my work that very often I need to update some map frames because data I am presenting in map changed or I need to add/remove layer, change scale, projection etc.  So if I create one map frame, lock it (Lock layers for map item), create second map frame with different layers, scale,projection etc. and than realize I need to change something in first frame, I can't find a simple way to do it...  To simply do that in Mapinfo, there are more Map Windows, in ArcGIS there are multiple Data Frames. What is in QGIS to achieve that? How would I have a  action that may have some effects on the current page but would also change the URL in the browser so if the user hits reload or bookmark, then the new URL is used?    It would also be nice if the back button would reload the original URL.  I am trying to record JavaScript state in the URL. input() error - NameError: name '...' is not defined LaTeX Error: Option clash for package xcolor I have an option clash between package xcolor and another package, but I don't know which. Here is my MWE  \documentclass[10pt]{beamer} \setbeamertemplate{navigation symbols}{} \usepackage{caption} \usepackage{subcaption} \usepackage{url} \usepackage{color} \usepackage[usenames]{xcolor}  \author{The author} \title{Package conflicts} \date{October 3rd, 2012}  \begin{document}  This is supposed to be \textcolor{olivegreen}{olivegreen} \end{document}   And the error message is :  This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009/Debian) entering extended mode (./error_xcolor.tex LaTeX2e &lt;2009/09/24&gt; &lt;blablabla&gt; ! LaTeX Error: Option clash for package xcolor.   I hope this is enough log for you guys. At this time of the day, I'm hoping for America to save my french ass ... again : ) (Disclaimer: I've read the  and I do understand that this is bordering on off-topic since it's about consumer devices. However I hope that I've managed to make enough on-topic by asking about why it is the way it is, and what is the explanation from an electromagnetic point of view - in other words, what laws of electricity and what practical considerations have gone into these decisions).  I recently bought a power tool and in its manual I found a few peculiar safety rules. I cannot see why they would be there, although reading up more it seems that they are commonplace. My understanding of electricity is limited (just about enough to be dangerous), so I'm hoping to expand it. :)  The rules are:   Don't use an extension cord longer than 25m. Considering this is an outdoors tool, this limitation is severely restrictive. The best explanation I've seen is that longer cables would simply have too high of a resistance and the tool wouldn't be able to operate at full power. But this argument doesn't convince me. The tool is rated at 2.4kW, and it's meant to be used with 220V AC power source, which means it uses about 11 amps of current. All the extension cords I've ever come across have at least 16A limitation, so there is quite a reserve still. In addition, the power has to travel much, much further to get to my house, and even after the meter it still takes probably close to those same 25m to get to the power outlet. Why only 25m after the outlet? The resistance of the cables isn't that big, is it? Don't daisy-chain extension cords. I suspect this is a variation of the above - don't exceed 25m; every connection adds additional contact resistance; water in the outdoors connections can be a problem - in general, it just adds risk. However, apart from the water in the contacts, the rest seems to me to be practically negligible. Is there really a significant contact resistance? Assuming that the extension cords are in a good shape. Make sure that the power cord is entirely unrolled. This is another odd one. My suspicion is that it has to do with inductive resistance. But is it really that strong? Wherever I've seen people actually wanting to create an electromagnet, it's pretty much hard work. You need a lot of neat, tightly-wound loops of wire. An extension cord has a lot of insulator around it, spacing the wires pretty far apart, and the loops are very chaotic. In addition, if that was a problem, why do  exist? They're used especially when you need a very long extension cord, and you don't need to unroll them completely every time you want to use them. Solved: OK, I was off the mark. The correct answer (also a ) has to do with the wire heating up from being used close to its limits. When coiled together, the temperature can go pretty high and melt the cables. Not fun. Number of $n^2\times n^2$ permutation matrices with a 1 in each $n\times n$ subgrid I found the following question in a paper I was trying to solve:  The following figure shows a $3^2 \times 3^2$ grid divided into $3^2$ subgrids of size $3 \times 3$. This grid has $81$ cells, $9$ in each subgrid.    Now consider an $n^2 \times n^2$ grid divided into $n^2$ subgrids of size $n \times n$. Find the number of ways in which you can select $n^2$ cells from this grid such that there is exactly one cell coming from each subgrid, one from each row and one from each column.  My try:  Since we have $n^2$ rows, $n^2$ columns and $n^2$ subgrids in total, we have to choose one and only one cell from each of them. Let's choose them one at a time. We can choose the first cell in $n^4$ many ways. Then, we'll have to avoid that subgrid, that column and that row that we've chosen the first one from when choosing the second cell. So, we have $n^4-n^2-2n(n-1)$ choices. We can continue this to get the total number of possible ways. But, I think there's a hole. Say, we've chosen the first cell from the subgrid of the up-left corner and the second from the subgrid just right to it so that it doesn't violate any rules. Then, when finding the number of ways we can choose the third cell, we would have substracted some of the cells twice. I think you get it. Please, if anyone can help me solving this problem, it'd be greatly appreciated. Android OS without Google Services? I'm having problems with a WFS GetFeature request. I'm using OpenLayers with an OSM map as base layers which use the Google projection. Overlaying the layer with WMS works perfect. When I do a request to return all features within the bounds of a polygon, no features are found.  My layer uses EPSG:28992. the base layer uses: EPSG:900913  My layer configuration in GeoServer:    When I set the declared SRS to EPSG:900913 and set "SRS handling" to "Reproject native to declared" it works fine, but I need OpenLayers to reproject it, not GeoServer.  Below is an example request I would do. I think the problem is that GeoServer does not convert the spatial filter to the native SRS.  http://mydomain.com/wfs?request=GetFeature&amp;version=1.1.0&amp; srsName=epsg:28992&amp; typeName=Namespace:Layer1&amp; propertyName=(*)&amp; CQL_FILTER=year = 2011 and INTERSECTS(geometry,POLYGON((565585.61613069 6816272.786200799,565585.61613069 6817032.3791692,564362.62367835 6817032.3791692,564362.62367835 6816272.786200799,565585.61613069 6816272.786200799)))&amp; outputFormat=GMl2&amp;   Update  I just tried re-projecting some points from OpenLayers (EPSG:900913) via proj4js to EPSG:28992 (PostgreSQL and GeoServer). I took 3 points and  compared them. They all showed an offset.   Converted: POINT(233492,24349424947 582191,0681508556)  In Database: POINT(233530,852147064 582315,680920578)  Difference x: 38,60865281453 Difference y: 124,6127697224 Converted: POINT(133459,1980658749 455770,7481867363)  In Database: POINT(133486,356985081 455879,67223342)  Difference x: 27,1589192061 Difference y: 108,9240466837 Converted: POINT(176920,43262818802 317930,36182729155)  In Database: POINT(176954,154083767 318023,515324756)  Difference x: 33,72145557898 Difference y: 93,15349746445   If the offset was constant I could correct it. Now I'm not sure if the offset is caused by GeSserver or by proj4js. I'm guessing proj4js since the WMS layer does not show any offset. What is the exact difference between an autoregressive (AR) and vector autoregressive model (VAR)?  I always thought that VAR would just be for more than two variables, until I learned that AR can also have more than two variables. I.e. I had a misunderstanding(?) that AR models are not always bivariate.  Before I write too much potentially false assumptions about the difference between AR and VAR, it would rather be interested to see if anyone can make provide a quick and good summary. How do I alter a message in the message queue independent of site language? I want to programatically alter a message in the message queue. The message I want to alter is set in the message queue by function comment_form_submit() in comment.module, i.e.:  if ($comment-&gt;status == COMMENT_NOT_PUBLISHED) {   if (!user_access('administer comments')) {     drupal_set_message(t('Your comment has been queued for review by site administrators and will be published after approval.'));   } }   Instead of this, I want the call to drupal_set_message() to be this:  drupal_set_message(t('Your comment will be published when you validate your e-mail address.'));   How do I do this?  Postscript: Based on the answer below by Topsitemakers, I got this working for any language by using array_search() inside a custom MYMODULE_comment_submit to search the message array, and then compare the translated strings to identify the key of the string to alter.  This is the working code I ended up with:  $mm = drupal_get_messages('status', TRUE); $key = array_search(t('Your comment has been queued for review by site administrators and will be published after approval.'), $mm['status']); if (FALSE !== $key) {   $mm['status'][$key] = t('Your comment will be published when you validate your e-mail address.'); } foreach ($mm['status'] as $msg) {   drupal_set_message($msg, 'status'); } How to get sitelinks to appear on Google Search? Distribution of the maximum of two correlated normal variables Jewish Law prohibits the  However, butter, a milk product, is a kitchen staple for most cooked emulsions (eg. pan-sauces, sauces béchamels, or roux-based sauces). While I use appropriate cooking fats for making non-dairy versions for meat dishes, this frequently doesn't work.  What is a non-dairy fat which may be used to as an emulsifier or roux ingredient? crisscross, dillydally, riffraff, etc Some English words only differ in their vowels: crisscross, dillydally, riffraff, etc. Is there a name for them? How do they film continuous blood pooling? What is spin as it relates to subatomic particles? I often hear about subatomic particles having a property called "spin" but also that it doesn't actually relate to spinning about an axis like you would think. Which particles have spin? What does spin mean if not an actual spinning motion? found a 1994 uncashed profit sharing retirement plan check I found an old un-cashed check dated 1994 for $487 from my Xerox Retirement plan with no expiration date. Can I still cash it? I can't install VMwarePlayer 4.0.3 on Ubuntu 12.04 64Bit. For Version 4.0.2, I found a script that I have to run to patch VMware Player for it to work on my system to properly, and after that I could install 4.0.2.  Is there an similar solution for Version 4.0.3?