Android app not able to do a task after comparing a phone number
How do I compare strings in Java?
Unable to install VLC This is what happens:  sudo apt-get install vlc Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package vlc   Please help. I would also like to know when this error occurs, I've seen it before too. Subscribers currently in a Journey What ways could you create a data extension that contains all the subscribers (SubscriberKeys) that are currently “in” a Journey (Journey Builder)?  The Journey I would like to do this for is a complex activity with multiple decision branches resulting in multiple possible journey durations. For example; if the customer didn’t open Email1 after 2 days, then send Email2; else Exit Journey. If the customer didn’t open Email2 after 2 days, then send Email3; else Exit Journey. Wait 2 more days, then End Journey. The minimum journey duration for the above example is 2 days, while the maximum is 6 days.  Note that I don’t want a list of subscribers that “entered” a Journey, but a list of the ones that are “currently in” a Journey and have not yet exited. Answer must account for non-standard Journey exits including Unsubscribes/Contact Deletes, etc. What is the Ubuntu equivalent of this interface?    I am looking for a user-friendly method that the owner of a computer can use to log off other users without having to restart.  The case I'm concerned about is of the beginner-level user who needs administrative control over the computer because they are the owner, but probably isn't concerned with most of the tasks we would usually associate with system administration. What books are recommended for learning calculus on my own? I recently graduated with a degree in bachelor of science with a focus interactive and multimedia design. I had to opportunity to take 1 C++ course and 1 HTML course. I was also only required to take one math class, introduction to calculus (and it was hardly calculus, it was more of a math class for designers)  Since graduating I have pursued a career in web development. I'm considering going back for a MS in computer science or MS in web technologies.   I feel my math has suffered dramatically as I have always been behind most others on my math studies (middle school through college). I want to learn calculus as I feel it's an integral part of any CS degree.   Does anyone have any recommendations on any great books that I can read through and teach my self a bit of calculus or other advanced math topics?  Thanks for any advice Python rounding error with float numbers I have a dedicated server with 2 TB storage.   My problem is that the whole storage is allotted to the root partition.   Whenever I try to resize it using lvresize, the root partition gets corrupted and then I have to reprovision the server.   Is there any option to resize the root partition without unmounting in lvm?  I am trying to reduce the root partition to 100GB.  Vgs  root@s93079:/home/customer# vgs   VG        #PV #LV #SN Attr   VSize VFree   s93079-vg   1   2   0 wz--n- 1.82t    0   Lvs  LV     VG        Attr       LSize  Pool Origin Data%  Meta %  Move Log Cpy%Sync Convert   root   s93079-vg -wi-ao----  1.79t    swap_1 s93079-vg -wi-ao---- 32.00g   Fdisk - l  Device     Boot  Start        End    Sectors  Size Id Type /dev/sda1  *      2048     499711     497664  243M 83 Linux /dev/sda2       501758 3907028991 3906527234  1.8T  5 Extend /dev/sda5       501760 3907028991 3906527232  1.8T 8e Linux  Disk /dev/mapper/s93079--vg-root: 1.8 TiB, 1965782204416 byt es, 3839418368 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/mapper/s93079--vg-swap_1: 32 GiB, 34355544064 byte s, 67100672 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes   Vgdisplay   --- Volume group ---   VG Name               s93079-vg   System ID   Format                lvm2   Metadata Areas        1   Metadata Sequence No  3   VG Access             read/write   VG Status             resizable   MAX LV                0   Cur LV                2   Open LV               2   Max PV                0   Cur PV                1   Act PV                1   VG Size               1.82 TiB   PE Size               4.00 MiB   Total PE              476870   Alloc PE / Size       476870 / 1.82 TiB   Free  PE / Size       0 / 0   VG UUID               dPrEwA-77pM-pGai-9jZB-ldMZ-iL20-HAe9 Dj   lvdisplay /dev/s93079-vg/root   --- Logical volume ---   LV Path                /dev/s93079-vg/root   LV Name                root   VG Name                s93079-vg   LV UUID                bpGNau-XirV-P7PA-8d6k-OCOy-TAwN-HXl FVI   LV Write Access        read/write   LV Creation host, time s93079, 2016-08-27 09:22:05 -0500   LV Status              available   # open                 1   LV Size                1.79 TiB   Current LE             468679   Segments               1   Allocation             inherit   Read ahead sectors     auto   - currently set to     256   Block device           254:0   Lvdisplay /dev/s93079-vg/swap_1  --- Logical volume ---  LV Path                /dev/s93079-vg/swap_1  LV Name                swap_1  VG Name                s93079-vg  LV UUID                j74PLZ-E9gK-9Bbb-EkKq-xRJv-TuU4-FgH gm  LV Write Access        read/write  LV Creation host, time s93079, 2016-08-27 09:22:05 -0500  LV Status              available  # open                 2  LV Size                32.00 GiB  Current LE             8191  Segments               1  Allocation             inherit  Read ahead sectors     auto  - currently set to     256  Block device           254:1   Df - h  /dev/dm-0       1.8T  923M  1.7T   1% / udev             10M     0   10M   0% /dev tmpfs           3.2G  8.5M  3.2G   1% /run tmpfs           7.9G     0  7.9G   0% /dev/shm tmpfs           5.0M     0  5.0M   0% /run/lock tmpfs           7.9G     0  7.9G   0% /sys/fs/cgroup /dev/sda1       236M   33M  191M  15% /boot In his lectures on String Theory (), Tong gives a proof of the Weyl anomaly, using equation $(4.36)$. It seems wrong to me.  Here he uses the OPE between the stress-energy tensors $T_{zz}T_{ww}$  obtained when trace vanishes, i.e. $T_{z \bar{z}} = 0$: this implies that they are holomorphic functions $T_{zz} = T_{zz}(z)$. But in this proof he starts from the fact that $T_{z \bar{z}} \neq 0$ (we want to proof this thing after all) and so $T_{zz}$ is not a holomorphic function anymore! In the OPE $(4.36)$ I should have also terms with $(\bar{z}- \bar{w})$.  I can't also understand why he uses in the rest of the proof only the singular term $(z-w)^{-4}$, neglecting the other ones $(z-w)^{-2}$, $(z-w)^{-1}$.  (The same proof is given in these lectures  on conformal field theory, equation $(6.9)$).  I'll be really thankful if someone could explain me this proof :) Booting system without full network configuration I was trying to solve internet problems, and seem to have made things worse: Now when I start the computer it gets stuck on "Booting system without full network configuration".   Does anyone know how to make it unstuck?   Alternatively: It got messed up when I changed the contents of /etc/network/interfaces, so presumably would work again if I changed it back. How can I edit this file during boot?   I'm using Ubuntu 12.10. Function returns None without return statement Randomize a List What is the best way to randomize the order of a generic list in C#? I've got a finite set of 75 numbers in a list I would like to assign a random order to, in order to draw them for a lottery type application. I was going through fluid dynamics and I came upon this section on the shape of a liquid surface in a rotating cylindrical vessel. The working in the book is something like this:   It considers a mass $m$ of water on the surface of the rotating liquid at a distance $x$ from its axis of rotation .It takes into account a pseudo force ($m \cdot x \cdot \omega^2$) radially outwards and its weight force ($mg$).It then proceeds to calculate the net force and the angle it makes with the vertical.From there through basic integration it gets the equation of the surface of liquid  i.e. $y= \dfrac{(x^2 \cdot \omega^2)}{2g}$ .  I get this working.  But if I were to view the same rotation through an inertial frame,how would I proceed? I mean, there wouldn't be any pseudo force, rather a centripetal acceleration of same magnitude radially inwards.This is where I am facing certain doubts.  The forces on the liquid would be  the centripetal force inwards and the weight force downwards.The net force would therefore be in a different direction,and consequently the slope of the surface at that point would be in a different direction.How is it possible for the same surface to have two different shapes in two different frames?   I would be obliged if someone could help me out by pointing out the flaw in my understanding. I have a c++ header file containing a class. I want to use this class in several projects, bu I don't want to create a separate library for it, so I'm putting both methods declarations and definitions in the header file:     // example.h #ifndef EXAMPLE_H_ #define EXAMPLE_H_ namespace test_ns{  class TestClass{ public:     void testMethod(); };  void TestClass::testMethod(){     // some code here... }  } // end namespace test_ns #endif   If inside the same project I include this header from more than one cpp file, I get an error saying "multiple definition of test_ns::TestClass::testMethod()", while if I put the method definition inside the class body this does not happen:  // example.h #ifndef EXAMPLE_H_ #define EXAMPLE_H_ namespace test_ns{  class TestClass{ public:     void testMethod(){         // some code here...     } };  } // end namespace test_ns #endif   Since the class is defined inside a namespace, shouldn't the two forms be equivalent? Why is the method considered to be defined twice in the first case? Difference between $\Delta$, $d$ and $\delta$ When I'm looking down the front page on , I often wish I could tell at a glance what happened to the question to bump it there. Sometimes it is obvious from looking at the number of answers, other times you have to follow a link to find out if it has been edited or if an answer has been added or updated.  I'm guessing this is just as applicable on other SE sites - this is the kind of thing I'm suggesting:    A couple of suggestions from the comments that might be good:   To reduce clutter the word 'ago' could be removed at the same time. The new text could be visible only to established users - ie users who are likely to be reviewing/editing and would benefit from seeing at a glance what kind of change has occurred. can't create a jobs user profile I'm stuck on this page even after linking stackoverflow and github accounts. I can copy, move, create, and delete them. I can rename them using the REN command from a command prompt. I cannot rename folders through Windows Explorer anywhere on my machine, including on other drives.   When I try to do so, I receive an error titled "Rename Folder" that says "Can't find the specified file. Make sure you specify the correct path and file name." Then when I click Try Again or Cancel, I get another error titled "Rename" that says "The file or folder does not exist."  As far as I can tell, nothing else is wrong with my computer, but I'm pulling my hair out trying to fix this problem. I don't know for sure if superuser is the right place to ask this question, but feel free to redirect me.  Summary of Failed Attempts:   Booted into Safe Mode  Made a New User Account System Restore Point (two days ago, 9 days ago)  Deleting / Restoring / Modifying FolderDescriptions registry entries SFC /scannow  Removing windows update KB2984006  Scanned for viruses using Nod32  Scanned for malware using MalwareBytes   Details:  Tried rolling back to two different system restore points, both immediately before I observed the problem and one release prior to that.  Tried restoring FolderDescriptions registry entries as found here:   Booting in safe mode as suggested here:   SFC /scannow as suggested here:   Tried removing registry keys and windows update KB2984006 as suggested here:   Tried exporting folderdescriptions from other machine and importing as suggested here:   Compared my exported registry with other machine's exported registry for both:  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Explorer\FolderDescriptions   My FolderDescriptions branch of the registry in both cases are binary equal to those exported from my wife's Windows 8.1 laptop which works fine. How to show $\omega^n$ is a volume form in a symplectic manifold $(M, \omega)$? My laptop has a function key which turns F keys into keys which change volume or brightness. I would like to swap a number of them so that they perform that function under normal operation and are an Fx key while the function key is being held.  I assumed that the function keys were just normal keys codes with the set of keys being large enough to include all the possible speical keys. I tried to so as this tutorial suggests () and use xev to obtain the key codes and then would use xmodmap to swap their value.  This does not seem to work though. The F12 key gives the xev output:  KeyPress event, serial 41, synthetic NO, window 0x4a00001,     root 0xb1, subw 0x0, time 468005, (23,-15), root:(89,37),     state 0x10, keycode 96 (keysym 0xffc9, F12), same_screen YES,     XLookupString gives 0 bytes:      XmbLookupString gives 0 bytes:      XFilterEvent returns: False   Which I think is to be expected. However, the Increase Volume button give this response:  KeymapNotify event, serial 41, synthetic NO, window 0x0,     keys:  65  0   0   0   0   0   0   0   0   0   0   0   0   0   0   0               0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0    And so does the Decrease Volume key. How can I perform the swapping of the keys that I would like?  Thank you How to derive this binomial identity? How can I stand on the ground? EM or/and Pauli? There is this famous example about the order difference between gravitational force and EM force. All the gravitational force of Earth is just countered by the electromagnetic force between the electrons on the surface of my feet and the ground.  But also wave-function of electrons(fermions) do not overlap each other due to Pauli exclusion principle.  So which one is the true reason of me not flopping inside the earth forever? Is it only one of them(my guess is Pauli exclusion) or is it both?