I am using aura:iteration for the checkboxes as below--                      &lt;table class="slds-table slds-no-row-hover slds-                       table_striped"&gt;                         &lt;thead&gt;                             &lt;tr class="slds-text-title_caps"&gt;                                 &lt;th&gt;                                 &lt;/th&gt;                                 &lt;th&gt;                                     &lt;div class="slds-truncate" title="Column 1"&gt;Quote Id&lt;/div&gt;                                 &lt;/th&gt;                                 &lt;th&gt;                                     &lt;div class="slds-truncate" title="Column 1"&gt;View&lt;/div&gt;                                 &lt;/th&gt;                             &lt;/tr&gt;                         &lt;/thead&gt;                         &lt;tbody&gt;                             &lt;aura:iteration indexVar="index" items="{!v.listQuotes}" var="quote"&gt;                                 &lt;tr id="{!quote.Id}"&gt;                                     &lt;td&gt;                                         &lt;lightning:input aura:id="chkbox" id="{!quote.Id}" type="checkbox" onchange="{!c.checkboxSelect}"/&gt;                                     &lt;/td&gt;                                     &lt;td&gt;                                         &lt;div id="{!index}" class="slds-text-title slds-text-color_default"&gt;{!quote.Name}&lt;/div&gt;                                     &lt;/td&gt;                                     &lt;td&gt;                                         &lt;lightning:button name="{!quote.Id}" variant="base" label="View" title="View" onclick="{!c.viewQuote}" /&gt;                                     &lt;/td&gt;                                 &lt;/tr&gt;                             &lt;/aura:iteration&gt;                         &lt;/tbody&gt;                     &lt;/table&gt;   Now when I check the checkbox, I need to uncheck other checkboxes, so that at any given time I have just one Id with me.  I am not able to find a way to do that-- Here is what I tried--  checkboxSelect : function(component, event, helper) {     var quoteRecId = event.getSource().get("v.id");     var checkValue = event.getSource().get("v.value");      console.log('Inside checkbox Select--&gt;'+quoteRecId);      console.log('Inside checkbox Select checkValue--&gt;'+checkValue);      var quotes = component.get("v.listQuotes");     var resetChecks= [];     for(var i=0; i&lt;quotes.length; i++){         if (quotes[i].Id !== quoteRecId) {             component.find(quotes[i].Id).set("v.value", false);        }     }  }   Console Logs--  Inside checkbox Select--&gt;a0222000001ssxGAAQ EmployerViewQuotes.js:28 Inside checkbox Select checkValue--&gt;
I have two checkboxes in a lightning component, when we click on the first checkbox it marks true to the other checkbox, it works well only with the UI tags but doesn't work when I convert it to lightning tag  &lt;ui:inputCheckbox aura:id="box3" change="{!c.selectAll}"/&gt;  &lt;ui:inputCheckbox aura:id="boxPack" value=""                                                          change="{!c.checkboxSelect}"/&gt;   below are the lightning tags  &lt;lightning:input type="checkbox" aura:id="box3" onclick="{!c.selectAll}"/&gt;  &lt;lightning:input type="checkbox" aura:id="boxPack" value=""                                                          onclick="{!c.checkboxSelect}"/&gt;   controller  checkboxSelect: function(component, event, helper) {         // get the selected checkbox value           var selectedRec = event.getSource().get("v.value");         // get the selectedCount attrbute value(default is 0) for add/less numbers.          var getSelectedNumber = component.get("v.selectedCount");         // check, if selected checkbox value is true then increment getSelectedNumber with 1          // else Decrement the getSelectedNumber with 1              if (selectedRec == true) {             getSelectedNumber++;         } else {             getSelectedNumber--;         }         // set the actual value on selectedCount attribute to show on header part.          component.set("v.selectedCount", getSelectedNumber);     },      selectAll: function(component, event, helper) {         //get the header checkbox value           var selectedHeaderCheck = event.getSource().get("v.value");         // get all checkbox on table with "boxPack" aura id (all iterate value have same Id)         // return the List of all checkboxs element          var getAllId = component.find("boxPack");         // If the local ID is unique[in single record case], find() returns the component. not array            if(! Array.isArray(getAllId)){             if(selectedHeaderCheck == true){                  console.log('true');                 component.find("boxPack").set("v.value", true);                 component.set("v.selectedCount", 1);             }else{                 component.find("boxPack").set("v.value", false);                 component.set("v.selectedCount", 0);             }         }else{             // check if select all (header checkbox) is true then true all checkboxes on table in a for loop               // and set the all selected checkbox length in selectedCount attribute.             // if value is false then make all checkboxes false in else part with play for loop              // and select count as 0              if (selectedHeaderCheck == true) {                 for (var i = 0; i &lt; getAllId.length; i++) {                     component.find("boxPack")[i].set("v.value", true);                     component.set("v.selectedCount", getAllId.length);                 }             } else {                 for (var i = 0; i &lt; getAllId.length; i++) {                     component.find("boxPack")[i].set("v.value", false);                     component.set("v.selectedCount", 0);                 }             }          }        },
MBP 13' (mid-2010; 7,1) 2.4 Core 2 Duo P8600 supporting 16 GB RAM under Win7? I’ve got a MBP 13′ (mid-2010) 2.4 Core 2 Duo (full specs below) that I’m now operating solely under Win7 64Bit. It formerly run as well under OS X 10.6.8, relatively to which the firmware seems up to date (MBP71.0039.B0B).  Would my system recognize 16 GB RAM if operated under Win7 64 Bit? Or would it require the latest firmware (MBP71.0039.B0E) of OS-X 10.7.5 (which was never installed on my MBP) anyway?   As far as I have read elsewhere, using 16 GB RAM under OS X seems to definitely require this later version of OS X (including the respective firmware update); so I'd like to know whether this is an issue of OS X or (as I suspect) the firmware.    Modellname: MacBook Pro Modell-Identifizierung: MacBookPro7,1 Prozessortyp: Intel Core 2 Duo Prozessorgeschwindigkeit: 2,4 GHz Anzahl der Prozessoren: 1 Gesamtzahl der Kerne: 2 L2-Cache: 3 MB Speicher: 4 GB Busgeschwindigkeit: 1,07 GHz Boot-ROM-Version: MBP71.0039.B0B SMC-Version (System): 1.62f6 Why is the content of /run/resolvconf/interface/NetworkManager changed every time I reboot? $I_m - AB$ is invertible if and only if $I_n - BA$ is invertible. The problem is from  Algebra by Artin, Chapter 1, Miscellaneous Problems, Exercise 8. I have been trying for a long time now to solve it but I am unsuccessful.      Let $A,B$ be $m \times n$ and $n \times m$ matrices. Prove that $I_m - AB$ is invertible if and only if $I_n - BA$ is invertible.    Please provide with only a hint. My wife has a Nikon D3100 that I've been using to film, but the battery typically won't last through long shoots.  I've gathered from searching around that I can't charge the camera with USB, but I wondered if there's ANY way to do that. It seems at least possible that an adapter could exist that would fill in for the battery and plug into the wall, but I haven't been able to find such a thing.  Is there such a product or technique? It would be nice to not buy a second battery, I'm really hoping for a "set it and forget it" solution. Grub menu at boot time... "holding shift" not working I read here at  that holding Shift during boot can bring up the GRUB menu. However I try holding one or the other Shift keys, tapping, tapping then holding, nothing works. Am I missing something? How does one access the GRUB menu during boot time?   No dual boot here, just standard Lubuntu 14.04 install. Recently I bought a new laptop that came with Windows 10 installed but not activated. I use both Windows 10 and Ubuntu 18.04, so I tried making a dual boot with a USB flash drive. It was recognized by the BIOS, I tried Try Ubuntu without installing and Install Ubuntu. With both options the PC freezes, and I need to press the power button. It's shown very fast some errors that are listed below:  [ 0.064522] ACPI Error: Method parse/execution failed \_SB.PCID.RPOB.PXSX, AE_NOT_FOUND (20170831/parse-550)  [ 0.066316] ACPI Error: [_SB.PCID.RPOB.PXSX], Namespace lookup failure, AE_NOT_FOUND (20170831/download2-191)  [ 0.066325] ACPI Error: AE_NOT_FOUND, During name lookup/catalog (20170831/psobject-252)  [ 0.246232] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246248] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246260] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246272] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246285] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246297] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246310] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)  [ 0.246322] ACPI Exception: AE_NOT_FOUND. Evaluating _PRS (20170831/pci_link-176)   I'm using NVIDIA GTX 1050 Ti graphics card and Intel i7-8750H processor.  I talked to the customer support and they just said that my laptop might not be compatible with Ubuntu. I also tried Ubuntu 16.04, but there were no changes.  EDIT: Thanks a lot for all the answers, but unfortunatelly I returned the PC to the store, neither the technical support found a solution for the problem, they just said: "Our PCs are just able to work with Windows, anyother OS might work but without our warranty". VirtualBox not starting after kernel upgrade Yesterday I received a kernel upgrade and after reboot, VirtualBox stopped working.  Here is my system info (after kernel upgrade):  matteo@workstation:~$ cat /etc/lsb-release  DISTRIB_ID=Ubuntu DISTRIB_RELEASE=16.04 DISTRIB_CODENAME=xenial DISTRIB_DESCRIPTION="Ubuntu 16.04.3 LTS" matteo@workstation:~$ uname -a Linux workstation 4.4.0-116-generic #140-Ubuntu SMP Mon Feb 12 21:23:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux   I installed VirtualBox long ago with  sudo apt install linux-headers-$(uname -r) sudo apt install virtualbox-dkms virtualbox virtualbox-qt   used on daily basis and never had problems with kernel updates. The error I receive now is   matteo@workstation:~$ sudo modprobe vboxdrv modprobe: ERROR: could not insert 'vboxdrv': Exec format error matteo@workstation:~$ dmesg | tail -n 1 [ 1413.167311] vboxdrv: version magic '4.4.0-116-generic SMP mod_unload modversions ' should be '4.4.0-116-generic SMP mod_unload modversions retpoline '   I found a forum post with this error message  from three days ago, unfortunately without resolution. Therfore I tried to remove the VirtualBox packeges from the Ubuntu repo, and install the latest 5.2 using . However, even after rebooting the machine, the error remains.  What can I do in this case? I have some plasterboard screws like this:     However, without a drill I have a job getting them into the wall. Am I safe to use normal screws on hangings that aren't going to be taking a great deal of weight? In this case it is a rack of coat hooks. Is there an injective function $f :\mathbb{R}^2\rightarrow\mathbb{R}$?  I approached this problem from the perspective of $f^{-1}$, from which I showed there exists a surjective function $f^{-1}:\mathbb{R}\rightarrow\mathbb{R}^2$. Would this imply that there exists an injective function for the inverse mapping? I came upon an interesting way to relatively quickly compute modular exponentiation with large numbers. However, I do not fully understand it and was hoping for a better explanation.  The method basically states if you have $x^y \bmod N$, it can be computed by repeatedly multiplying by $x$ modulo $N$:  $$x \bmod N \rightarrow x^2 \bmod N \rightarrow x^4 \bmod N \rightarrow x^8 \bmod N \rightarrow \ldots \rightarrow x^{2[\log y]} \bmod N$$  This is supposed to calculate in $\mathcal{O}(\log_2 N)$ time.  An example is given:  $$x^{25} = x^{11001_2} = x^{10000_2} * x^{1000_2} * x^{1_2} = x^{16} * x^8 * x^1$$  I don't really understand how this is faster. Aren't you just doing the same thing? You're just breaking down the exponents into representations of base $2$. Also where does $x^{2[\log y]}$ come from? If you're breaking it down into exponents of two where does a logarithm come from? (Aren't logs representations of numbers in exponents of $10$?)  I'm sorry if this appears to be a really stupid question - I have minimal knowledge in math.  Also, I wasn't sure if this belongs here or on stack exchange, so give me the word and I'll move it. I have seen a few  here on Meta&nbsp;Stack&nbsp;Exchange that cover parts of this, but they are often too local, and none of them seem to cover all the relevant scenarios.  I will break it up into multiple parts in order to make this more specific:     When should I vote on a question:   What are the qualifications for a question to be deserving of being up-voted? When shouldn't I vote up on a question? What are the things that would cause a question to need to be down-voted?   How should I go about down-voting the question (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on a question?  When should I vote on an answer:   What are the qualifications for an answer to be deserving of being up-voted? When shouldn't I vote up on an answer? What are the thing that would cause an answer to need to be down-voted?   How should I go about down-voting the answer (do I wait a little while to give the OP a chance to change it, or do I down-vote it immediately)?  When shouldn't I vote down on an answer?  When should I vote on a comment:   While votes on comments do not affect reputation points, it might be useful to new users to know when to up-vote them.    It seems that a full, comprehensive list of these would be invaluable to new users looking to figure out how the voting system works, but this list seems to be missing from the meta site. Using Windows 10 in a virtual machine. Can it be done? I am currently running 8.1. I'd like to try out Windows 10 and if I like it upgrade. If not, I'll keep running as I am.   I've never used a virtual machine before: can Window 10 be used from a virtual machine as a "sandbox", and if so how? How can I get CSS comments with jQuery? I am wondering how I can read CSS comments out of a linked stylesheet.  I have this sample CSS loaded via:  &lt;link rel="stylesheet" type="text/css" media="all" href="test.css" /&gt;   &nbsp;  #test1{ border:1px solid #000; } #test2{ border:1px solid #000; } #test3{/* sample comment text I'm trying to read */}   I'm testing this in FF3. The following javascript reads the rules but doesn't read the comments in#test3.  window.onload = function(){     s=document.styleSheets;     for(i=0;i &lt; s[0].cssRules.length;i++){         alert(s[0].cssRules[i].cssText);     } } Exercise 3.5.12. Let $ f: \mathbb N \times \mathbb N \to \mathbb N$ be a function, and let c be a natural number. Show that there exists a function $a:\mathbb N\to \mathbb N$ such that $$a(0)=c$$ and $$a(n++)=f(n,a(n))\;for\;all\;n\in \mathbb N,$$ and furthermore that this function is unique. Tao gives the hint: first show inductively, by a modification of the proof of Lemma 3.5.12, that for every natural number $N\in \mathbb N$, there exists a unique function $a_N:\{ n\in \mathbb N:n\lt N\}\to \mathbb N $ such that $a_N(0)=c$ and $ a_N(n++)=f(n,a(n))$ for all $n\in \mathbb N$ such that $n\lt N$.  In my opinion, we could solve it by proving that $\forall n\in \mathbb N,a(n)\in \mathbb N$ according to mathematcial induction.  The property P(n) is:$$\forall n\in \mathbb N, a(n)\;is\;unique$$ P(0) is true. And if P(n) holds, P(n++) is true because different natural numbers must have different successors. $$a(n++)=f(n,a(n))$$ $$a(m++)=f(m,a(m))$$ $$n++=m++\Rightarrow n=m\Rightarrow a(n++)=a(m++)$$ It's similar to the proof of  Proposition 2.1.16 (Recursive definitions): Suppose for each natural number $n$, we have some function $f_{n} : \mathbb{N} \rightarrow \mathbb{N}$ from the natural numbers to the natural numbers. Let $c$ be a natural number. Then we can assign a unique natural number $a_{n}$ to each natural number $n$, such that $a_{0} = c$ and $a_{n{++}} = f_{n} (a_{n})$ for each natural number $n$.  This proof indicates both the existence and uniqueness of the function $a$. I don't know why Tao says it's informal.  But regarding the hint, how do we get the function f even if we've got the conclusion from the hint. Also it seems like the function a(n) can be diffentent considering different N. I don't know if the hint is correct. Context: I want to store the TIFF data to use it for running a linear regression model later on. Ultimate goal: Create a carbon map using field data as a basis. Libraries: library(sp) library(raster) library(tidyverse) library(rgdal)  plotcoord &lt;- SpatialPointsDataFrame(AGCplot[,3:4], AGCplot[,1:2],proj4string=CRS('+proj=longlat'))  pspcoord&lt;-spTransform(plotcoord, CRS('+proj=utm +zone=21')) #Omzetten naar UTM21N (= S1) plot(pspcoord)  s1 &lt;- stack('Some.tif')  colnamen = c(&quot;plotid&quot;,&quot;AGC&quot;,&quot;B2&quot;,&quot;B3&quot;,&quot;B4&quot;,&quot;B5&quot;,&quot;B6&quot;,&quot;B7&quot;,&quot;B8&quot;,&quot;B8A&quot;,&quot;B11&quot;,&quot;B12&quot;,&quot;NDVI&quot;,&quot;NDWI&quot;,&quot;MMRI&quot;,&quot;IRECI&quot;,&quot;MASI&quot;,&quot;VV&quot;,&quot;VH&quot;)  s1_e &lt;- extract(s1,pspcoord,method='bilinear')  Upon extraction I get the following message: Warning message: In proj4string(x) : CRS object has comment, which is lost in output I play D&amp;D 5e and sometimes come here with questions. But sometimes I see things referenced here as sources that I don't have or aren't aware of....  Which are the "official rules" for D&amp;D 5e, and where do I find them? Why must $\mathbb{Q}[\sqrt{2}, \sqrt{3}]$ -- the set of all polynomials in $\sqrt{2}$ and $\sqrt{3}$ with rational coefficients  -- contain multiplicative inverses?   I have gathered that every element of $\mathbb{Q}[\sqrt{2}, \sqrt{3}]$ takes form $a + b\sqrt{2} + c\sqrt{3} + d\sqrt{2}\sqrt{3}$ for some $a,b,c,d \in \mathbb{Q}$, and I have shown that $\mathbb{Q}[\sqrt{2}]$ and $\mathbb{Q}[\sqrt{3}]$ are both fields, but it's not clear to me why this allows for general multiplicative inverses to exist in $\mathbb{Q}[\sqrt{2}, \sqrt{3}]$. What is the value of $\sum\limits_{i=1}^\infty\dfrac{1}{p_{p_i}}$ where $p_n$ is the nth prime (and so $p_{p_n}$ is the $k$th prime, where $k$ is the $n$th prime) ?  Thus $\frac{1}{3}+\frac{1}{5}+\frac{1}{11}+...=$ ??  How do I efficiently decide if $\sum_{i=1}^\infty\dfrac{1}{p_{p_i}}\gt1$ is true without using a computer ?  I assume this infinite sum is an irrational number. Has this already been proven ? I'm currently the proud owner of Frost the horse. What I want to know is, what will happen to him if I ride another horse?  Obviously nothing will happen as long as I have him in sight, e.g. I'll be able to ride Frost to make him my horse again.  Scenarios  But what will happen if, before I get back on Frost, I fast travel somewhere? Will he return to where I originally stole him, will he disappear forever, or can I own two horses simultaneously?  Ownership?  If he goes back to where I originally stole him, will I have to steal him again, and therefore never be his true owner again?  Two Horses?  The reason I'm asking is because I want to get Shadowmere (the Dark Brotherhood horse) while keeping Frost. Is it possible to do this, or will riding Shadowmere make me lose Frost forever? So, somehow over the weekend, my 1GB USB flash drive has managed to become write-protected.  There is no switch on the stick, so I'm concluding that something has corrupted at some point.  Obviously I can't format it or remove.  The output from dmesg | tail is:  Buffer I/O error on device sdb1, logical block 328168 lost page write due to I/O error on sdb1 sd 73:0:0:0: [sdb] Unhandled sense code sd 73:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE sd 73:0:0:0: [sdb] Sense Key : Data Protect [current] Info fld=0x0 sd 73:0:0:0: [sdb] Add. Sense: Write protected sd 73:0:0:0: [sdb] CDB: Write(10): 2a 00 00 05 08 00 00 00 01 00 Buffer I/O error on device sdb1, logical block 328200 lost page write due to I/O error on sdb1   I think the second and final lines are a giveaway to corruption, but I don't know how to interpret this output.  Could someone help to see if this output gives any indication?  I usually eject the drive before removing it, but I may have been lax once or twice.  The data isn't critical, it's just bugging me.  Any suggestions on how to fix it (if the drive even can be) would be greatly appreciated.