What is this star mark in this print function call?    for i in range(int(input())):        s=input()       print(*["".join(s[::2]),"".join(s[1::2])])
In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2):
Why doesn't my "Nikkor AF" lens autofocus on my Nikon D3300? I was trying to look for an answer of mine earlier and did a search like this:  user:me SQLite RunInTransaction   The above found nothing. So I changed it to  user:me SQLite   Which found a bunch of things. I dug through the results and saw this snippet for :     From my experience, wrapping as many database calls as possible into a transaction speeds things up quite a bit: using (var db = new SQLiteConnection(dbPath)) { db.RunInTransaction(() => { …    Notice that the snippet contains both "SQLite" and "RunInTransaction". In looking at the post itself I noticed "SQLite" was in the question title and in my answer as code. I also noticed that "RunInTransaction" is only in my answer in code.  I looked at meta and saw , which says I need to prefix any code with code:, so I tried:  user:me SQLite code:RunInTransaction user:me code:SQLite code:RunInTransaction   None of the above returned any results.  I also found  on meta which says I can search for code like this (without the code: prefix):        So I tried:  SQLite RunInTransaction "SQLite RunInTransaction"   The first did not return my answer. The second did not return any results.  So my question:  How do I properly search for , that has both "SQLite" and "RunInTransaction" in the post? I have recently installed Ubuntu 14.04 LTS on my laptop Sony Vaio VPCEA16FG. I have been getting system freezes (everything including display, mouse, keyboard stops working and I have to do a restart with the power switch) and there are random popups of "System program problem Detected"  On startup my screen is all splashed with black and white pixels and a System program problem detected message.  My video card info:    01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Madison [Mobility Radeon HD 5650/5750 / 6530M/6550M If a derivative of a continuous function has a limit, must it agree with that limit? Partner with "traditional" forums to support open ended discussions Why is the mol a fundamental physical quantity? I am starting to study physics in detail and as I read about physical quantities, I was puzzled why mol (amount of substance) is taken as a physical quantity.  A physical quantity is any quantity which we can measure and has a unit associated with it. But a mol represents the amount of substance by telling the number of particles (atoms, molecules, ions, etc.) present. So it is a pure number and numbers are dimensionless. So mol should not be considered a physical quantity.  Also, fundamental physical quantities should be independent of each other. I am wondering whether mass and mol are independent. This is so as they surely affect each other as we can evidently see while calculating the number of moles and using the mass of that sample for calculation.  So how is the mol a fundamental physical quantity and independent of mass? I have a stubborn folder that someone must have created accidentally and that has persisted all this time. I can see it with:  # find /var/www/html -maxdepth 1 -type d   which gives me:  /var/www/html /var/www/html/files /var/www/html/.?   unfortunately the question mark there is not the actual character ?, it merely seems to denote that there is no proper glyph and/or translation for that character. So something like rmdir is out of the question. My system has UTF-8 as the default locale as so many modern Ubuntu systems, but admittedly the folder in question may have originated on a RHEL or CentOS box (tared up and unpacked).  # env|grep LANG LANG=en_US.UTF-8   When trying to cd .\? (as mentioned before it is not actually ?) I get auto-corrected to . by bash and actually end up in /var/www/html/. for some reason. Now if I can't "name" this folder usefully, I cannot access it in any way. How can I get rid of it without putting the whole system in jeopardy?  Now I installed detox already but that only seems to act on files, not folders, according to its documentation and besides it still requires that I be able to name the object somehow to do something with it. What does it mean to instantiate a trait? Lag compensation with networked 2D games I want to make a 2D game that is basically a physics driven sandbox / activity game. There is something I really do not understand though. From research, it seems like updates from the server should only be about every 100ms. I can see how this works for a player since they can just concurrently simulate physics and do lag compensation through interpolation.  What I do not understand is how this works for updates from other players. If clients only get notified of player positions every 100ms, I do not see how that works because a lot can happen in 100ms. The player could have changed direction twice or so in that time. I was wondering if anyone would have some insight on this issue.  Basically how does this work for shooting and stuff like that?  Thanks In particular, I am referring to the Pearson product-moment correlation coefficient. What lifetime can be expected of the typical hard disk? Or are there big differences between different types? And does it make a difference if it is used heavily instead of never being connected to system (for example serving as a backup medium)? Is there a word to describe a highly desirable cursed treasure? We are using following code in .php script for generate .pdf file.  $result1 = exec("R CMD Sweave /var/www/html/r/r_latex_sweave.Rnw");  $result2 = exec("pdflatex /var/www/html/r/r_latex_sweave.tex");   but, we are getting this errors when we are executing .Rnw and .tex files.  ! I can't write on file `r_latex_sweave.log'. Please type another transcript file name:  ! Emergency stop !  ==> Fatal error occurred, no output PDF file produced!  Note: We have .tex and .Rnw folder in /var/www/html folder? SCP fails without error I am unable to understand what exactly is critical value.My question here is why do we fail to reject a null hypothesis when the test statistic is within the range of critical value.  What i am trying to ask is what is the property of the critical value that makes the hypothesized value to fall within the range implied by the critical value.  Thanks in advance Combining two expressions (Expression>) I have two expressions of type Expression&lt;Func&lt;T, bool&gt;&gt; and I want to take to OR, AND or NOT of these and get a new expression of the same type  Expression&lt;Func&lt;T, bool&gt;&gt; expr1; Expression&lt;Func&lt;T, bool&gt;&gt; expr2;  ...  //how to do this (the code below will obviously not work) Expression&lt;Func&lt;T, bool&gt;&gt; andExpression = expr AND expr2 I have a user control that I load into a MainWindow at runtime. I cannot get a handle on the containing window from the UserControl.   I have tried this.Parent, but it's always null. Does anyone know how to get a handle to the containing window from a user control in WPF?  Here is how the control is loaded:  private void XMLLogViewer_MenuItem_Click(object sender, RoutedEventArgs e) {     MenuItem application = sender as MenuItem;     string parameter = application.CommandParameter as string;     string controlName = parameter;     if (uxPanel.Children.Count == 0)     {         System.Runtime.Remoting.ObjectHandle instance = Activator.CreateInstance(Assembly.GetExecutingAssembly().FullName, controlName);         UserControl control = instance.Unwrap() as UserControl;         this.LoadControl(control);     } }  private void LoadControl(UserControl control) {     if (uxPanel.Children.Count &gt; 0)     {         foreach (UIElement ctrl in uxPanel.Children)         {             if (ctrl.GetType() != control.GetType())             {                 this.SetControl(control);             }         }     }     else     {         this.SetControl(control);     } }  private void SetControl(UserControl control) {     control.Width = uxPanel.Width;     control.Height = uxPanel.Height;     uxPanel.Children.Add(control); } Is it possible to migrate programs from 32 bit Windows to a new 64 bit Windows machine (both Windows 7)? I've got a Windows 7 Pro 32 bit PC. Getting a new Windows 7 Home 64 bit.  Is there anything I can use to transfer my  programs (the ones that don't come in a 64 bit flavor)  to the new PC? There is a related  that doesn't address the programs part. When we refer to a house that belongs to a family, we say "family's house". Pluralizing family gives us "families". Referring to the houses of several families, we say "families' houses". Forming the plural possessive in such a case is rather simple.  I encountered a more complex use of this recently - referring to a single house owned by a single family in a set of houses owned by a set of families.  We can say "the families' houses" to refer to all of the houses owned by all of the families.  We can say "one of the families' houses" to refer to one of the houses owned by one or more of the families. In this context, "one of" applies to "the families' houses".  If we were instead to apply "one of" to "the families", and want to refer to the one house owned by "one of the families", how would this be written?  My first though was "one of the families's house", taking "one of the families" as a single noun and appending 's to it. This looks (and sounds) a bit strange, though. "One of the families' house" and "one of the family's house"/"one of the family's houses" seem wrong to me, and I can't really determine the correct way to say/write this.  Is there a definitively correct way that this should be written?  EDIT: To clarify, although I think I made it clear, in this context, there are several families, and each owns one house. The goal of the sentence is to refer to one of those houses without stating which specific house. Example: "The players and their families want to celebrate their team's victory; this will likely entail a party at one of the families's house". Cleaning Contaminated Disc Rotors I've had an eternal struggle with my current bike over brake contamination. The levers and calipers are shimano ultegra r8000, so the latest and (almost) greatest.  I first noticed it when I took it to a repair shop (i no longer use) for a bleed, it came back and the front brake would squeal like crazy and at low speeds had little to no braking force. You can stop from speed but then struggle to come to a halt without using your foot.  At around 2000 miles I tried to replace the brake pads, when I took them out they were black with grime on both sets (front &amp; back), not to mention worn down to the metal. I replaced them with the L04C sintered pads, gave the callipers a good cleaning with a towel (no chemicals) and fitted the new set.  Annoyingly all of my braking issues are back, now I probably should have cleaned the rotors, I simply used some muc off disc brake cleaner on them. I would like to know the best way to clean the rotors, I've inspected the pads and they are looking fairly black now, with plenty of tread left. I'm going to abandon these pads and fit a new set. For the rotors I plan to completely remove them from the wheels (they are center lock fitted) and try and treat them off the bike, what is the best way to fully clean them? They have plenty of wear left in them but you can see these black grooves in them, and plenty of muck on the back that I struggle to get off.  Below are images of the rotors after soaking them in disc brake cleaners, waiting and then wiping them down with a clean, microfiber towel.   Front Wheel Outside Rotor   Front Wheel Inside Rotor - note the increased dirt on this side  Looking at ways people clean their disc rotors, I've seen plenty of suggestions that I would need to burn the contaminants off the discs. Would the best approach be to remove them and use a blowtorch, should I soak them in some nasty chemicals overnight before I try to heat them? Do I try baking them in the oven?  And finally, what is the best way to prevent the brakes from becoming contaminated in the future? it's really off putting when they squeal and don't perform how I'd expect because it means I'm more reserved whilst out riding on the bike, leading to reduced time riding around outside. I commute on this bike (50 miles a week) and then ride about 50 on the weekends also, so it see's it's fair share of road use. I tend to wash it once after my big ride on saturdays and will rinse it off if it's been raining, any day that occurs (since I live in north east england, the acid rain..). I've owned disc brake bikes before and never had half the issues I've had with this, I had a cheap trek with tektro brakes and the brakes were sharper and never had any issues with contamination whatsoever (i did around 500 miles on that bike before a motorist happened).  Thanks for any and all advice :)