this is my first time asking on stackoverflow, and I have a trouble when programming with python 2.7. Here I have a calculation: 1350/2.7  The exact answer must be 500, but python give the answer 499.99999999999994  I know about the fact that some numbers cannot be represented exactly in binary, causing error on floating calculation.  So can anybody give me an advice? How to deal exactly with it?
Consider the following code:   0.1 + 0.2 == 0.3  -&gt;  false   0.1 + 0.2         -&gt;  0.30000000000000004   Why do these inaccuracies happen?
Can't install aircrack-ng Whenever I attempt to install aircrack-ng in terminal I get the following error:  Package aircrack-ng is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it:   iw  E: Package 'aircrack-ng' has no installation candidate"   I'm new to Ubuntu and so have no idea what to do. novel with psi slavery Duplicate questions without answers Orthogonal matrix and orthonormal columns Cards changing mana color What cards across all sets allow the utilization of mana, either colorless or otherwise, as colored mana of another color?  One early example with an unlimited  1:1 ratio:     Sunglasses of Urza   Continuous Artifact: White mana in your mana pool can also be used as red mana.   What other cards have similar abilities? When should I use double or single quotes in JavaScript? console.log(&quot;double&quot;); vs. console.log('single'); I see more and more JavaScript libraries out there using single quotes when handling strings. What are the reasons to use one over the other? I thought they're pretty much interchangeable. Installing firmware blob for Intel Wifi USB pen I have installed Debian 8/Jessie minimal ISO on my laptop. I get error message during system installation:  Some of your hardware needs non-free firmware files to operate. The firmware can be loaded from removable media, such as a USB stick or floppy. The missing firmware files are: iwlwifi-7265-9.ucode iwlwifi-7265-8.ucode If you have media available now, insert it, and continue. Load missing firmware from removable media?  I found the appropriate firmware on Debian website, downloaded it (zip), extracted to flash drive, and booted with flash drive plugged in. I still get the error message that appropriate firmware could not be found (the error message disappear to fast to copy down). How do I properly format the flash drive? Or is the problem here something else? Windows Explorer on another computer tells me the flash drive is 14.6GB and formatted as FAT32. How to change font-size, number of rows / columns in the console I'm running a Linux server without X11 or any kind of GUI, with a modern 22" LCD monitor.  Given the huge size of my monitor, I would like to increase the number of rows and columns in my console, how can I go about achieving it? Re-entering the US for the third time in a year with total of 240 Days I went to the US for 90 days on an ESTA in August to November. Then back to my home country for 1 month and then back again mid December until mid February and now I am going back again after 10 days for another 90 days. Now I can see that some people refer to 180 day rule in a year. My stay will be 240 days in one year with short gaps between coming back. Is the 180 day rule accurate? Some people write that you can do unlimited trips to The US as long as you don't stay more than 90 days. Is that correct? My reason for going there the first time was to visit and travel with an American friend.  After my first visit (she is my girlfriend) moved with me to my home country but has ended up in a custody battle in the US so she needed to return urgently so I returned only to be with her and support her, not to be a tourist.  Then after my second visit I needed to go back to my sick Dad and to rent out my apartment since we left in a rush to go back to the US.  Now, my third visit is to continue to be with my girlfriend and support her in her difficult situation.   My question is, if I do end up in trouble should I tell them this whole story? Or should I just say I am visiting a friend for a third time because I want to see more of the country and I have some more time off before I go back to my job.  I have proof of money in my bank account and I stay and eat with her for free Documented proof that I have a job to return to in my home country My return ticket printed and an address to stay at in the US and I have proof I have an apartment in my home country Javascript Date: next month prints out a lot of very detailed protocol statistics like number of TCP reset messages received or number of ICMP "echo request" messages sent or number of packets dropped because of a missing route.  When in Linux netstat is considered deprecated at nowadays, then is there an alternative?  Statistics provided by ss -s are superficial compared to the ones provided by netstat. If $\omega \in \Omega^q(M)$, and $(\omega|_{U})_p = 0$, is $\omega_p = 0$? How to move 100 files from a folder containing thousands? I have a directory with thousands of files. How can I move 100 of the files (any files will do) to another location. How to pass the output of one command as the command-line argument to another? So I have a script that, when I give it two addresses, will search two HTML links:  echo "http://maps.google.be/maps?saddr\=$1\&amp;daddr\=$2" | sed 's/ /%/g'   I want to send this to wget and then save the output in a file called temp.html. I tried this, but it doesn't work. Can someone explain why and/or give me a solution please?  #!/bin/bash url = echo "http://maps.google.be/maps?saddr\=$1\&amp;daddr\=$2" |  sed 's/ /%/g' wget $url nmake fatal error U1034: syntax error : separator missing My stance is that these websites are a great boon to the research community and they were certainly extremely helpful for my research. I think they should be applauded rather than persecuted, and while they may be illegal now, I think a way to make them legal should be found (in the same way I can download articles legally through my university's subscription to all the major publishers and journals).  Can I thank them in the acknowledgements section of my thesis? SEO and buying expiring or dropped domain Does it make any difference for SEO benefits to buy dropped and already available domains other than backorder domains that are expiring soon?  I heard somewhere that whois gets deleted after being dropped. But I didn't find any confirmation if it's true or not.  Anybody can tell me if there are benefits of one against the other, if yes what? What is the difference between a homepage link with or without a trailing slash? There is a kind of situation that seems to occur somewhat commonly, that goes something like:   Figure out some way to handle a particular situation do it regularly, and make a habit of it, as it seems to work OK … … and only much later actually realize that it very much isn’t OK, that it’s been doing harm all the time, and that it’s too late to fix anything.   Does there exist any good words or phrases for this kind of situation? I hope I'm right in thinking this is the site where you post general computer-related problems...  A problem I have when playing games (since you won't be pressing multiple keys simultaneously anytime else), is that when I press up/left and then another key, it fails to 'register' as if that last key is never pressed. This doesn't happen when I'm pressing any other two arrow keys, e.g. down/left or up/right. The weird thing is that when I'm playing with WASD instead of the arrow keys, i still have this problem! Meaning W+A+another button doesn't work.  If anyone knows what I should, I'd appreciate the help. (My reflexes are fast and I can always circumvent this problem, but it's quite annoying and shouldn't exist to begin with!)