Merge two datasets of different lengths, R
Merge two data frames while keeping the original row order
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You can see all the ads that currently make the threshold and meet our criteria on this page:  You can also view the ads that meet the threshold using 's Finding a basis for a certain vector space of periodic polynomials Ubuntu installation does not recognize drive partitioning I have a 1TB drive and installed Windows 7 on a 128GB partition.  When I now try to install Ubuntu 11.04 it does not recognize the Windows partition but offers the complete 1TB drive to install Ubuntu on instead. It displays:    However, in the Ubuntu Disk Utility the Windows partitions are recognized.    What do I need to do in order for Ubuntu to recognize the Windows 7 partition and install Ubuntu as a dual boot?   Response to comments  The following commands were executed and the results are shown below:  fdisk -l  WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk  doesn't support GPT. Use GNU Parted.  Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x34a38165     Device Boot      Start         End      Blocks   Id  System /dev/sda1   *           1          13      102400    7  HPFS/NTFS Partition 1 does not end on cylinder boundary. /dev/sda2              13       16318   130969600    7  HPFS/NTFS  Disk /dev/sdb: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x14a714a6     Device Boot      Start         End      Blocks   Id  System /dev/sdb1               1       60801   488384001   83  Linux   parted -l  Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only. Error: /dev/sr0: unrecognised disk label In C++, sizeof('a') == sizeof(char) == 1. This makes intuitive sense, since 'a' is a character literal, and sizeof(char) == 1 as defined by the standard.  In C however, sizeof('a') == sizeof(int). That is, it appears that C character literals are actually integers. Does anyone know why? I can find plenty of mentions of this C quirk but no explanation for why it exists. I'm trying to find the derivative of $\sin^{-1}(x)$. I know the steps that lead to $\frac{1}{\sqrt{1-x^2}}$, however I don't understand why the following reasoning leads to a wrong answer.  Because  $$\frac{d}{dx}f^{-1}(x) = \frac{1}{f'(f^{-1}(x))} $$  If we plug in for $f(x) = \sin(x)$, and because $\frac{d}{dx}\sin(x) = \cos(x)$ we get  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\sin^{-1}(x))} $$  Since $\sin(x) = \cos(x-\frac{\pi}{2})$, we can state that $\sin^{-1}(x) = \cos^{-1}(x-\frac{\pi}{2})$. (I suspect this is what is wrong)  Thus,  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\cos^{-1}(x-\frac{\pi}{2}))}$$  Then, by the definition of inverse function, we have  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{x - \frac{\pi}{2}}$$ Does "the same number of people" behave as singular or plural? This hurts my eyes to read it and my ears to say it, but the writer stands by          About the same number of people was awarded bachelor's degrees in 2010 as filed for personal bankruptcy (1.6 million).   Is the subject in this sentence singular or plural? How do I run a program with commandline arguments using GDB within a Bash script? What are Click packages? I noticed that Ubuntu SDK recently had some updates and it installed a program named "Click". I would like to know what they are and how to use them.  Also, would they make Debian packaging easier? I'm using a 5 V / 2 A voltage regulator () without a heatsink. I'm testing the circuit with a microcontroller (PIC18FXXXX), a few LEDs and a 1 mA piezzo buzzer. The input voltage is aprox. 24 VDC. After running for a minute, the voltage regulator starts to overheat, meaning it burns my finger if I keep it there for more than a second. Within a few minutes it starts to smell like it's burnt. Is this a normal behavior for this regulator? What could cause it to heat that much?    Other components used in this circuit:  L1:   R2:   F1: Is it grammatically  wrong  to say      It's been too hot  in the last / the past few days      It's been too hot for the last / the past few days     I saw this following sentence also, can we omit in it?     He's had two new cars in the last / in the past three years   as     He's had two new cars  the last / in the past three years     Is there a strict rule in using of preposition or non-preposition when we use the last/past ?  What is the structure when I refer to weeks, months ? Is there an MD5 Fixed Point where md5(x) == x? Is there a fixed point in the MD5 transformation, i.e. does there exist x such that md5(x) == x? Set same icon for all my Forms Is there any way to set the same icon to all my forms without having to change one by one? Something like when you setup GlobalAssemblyInfo for all your projects inside your solution. How can I instantiate a generalized hash function? I've come across a bunch of "strange" hash function notations, such as the following ones and now I don't know how to choose / instantiate them.  Can you please explain me what this notation means and how I can actually instantiate such a hash function?  The notation in question: $$H_1:\mathcal M \rightarrow \mathbb F_p$$ $$H_2:\mathcal M \rightarrow \mathbb Z_n^*$$ $$H_3:\mathcal M \rightarrow \{0,1\}^l$$ $$H_4:\mathcal M_1\times ...\times \mathcal M_k\rightarrow \mathcal S$$  where $\mathcal M\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^*,\mathbb G,...\}$ where $\mathbb G$ is a generic (but there instantiated) group and $\mathcal S\in\{\mathbb F_p,\mathbb Z_n^*,\{0,1\}^l\}$ Is it possible to download using the Windows command line? Without using any non-standard (Windows included) utilities, is it possible to download using the Windows command line?  The preferred version is Windows XP, but it's also interesting to know for newer versions.  To further clarify my question:   It has to be using HTTP The file needs to be saved Standard clean Windows install, no extra tools   So basically, since everybody is screaming , I want simple Wget functionality, without using Wget. Is "shined" correct? If so, is "he shined X on the tree" also correct? Recently, I overhead a former professor of mine use the word shined, a word that makes me grammatically uncomfortable.  She used it as following: "Then, after we shined a light on the other ball, what happened?..."  My first question is: Is using shined mainstream, over what sounds better to my ear, shone?  If so, is there any historical flip-flopping between the two usages?  Secondly, if shined is in fact legit, can it be used transitively?  Saying something like,      The light shined all throughout the night.   while odd, doesn't sound as bad to my ear as,     He shined the light on the ball throughout the night.   The latter sounds quite bad to my ear.  Indeed, à propos the original question, can shone &mdash; the better sounding alternative to my ear &mdash; be used transitively? Definitions of connected space I have seen several definitions of connected space, but I would like to discuss those from . I am concerned about these:  $X$ is disconnected, if it is the union of two disjoint nonempty open sets.  What about $[0,1] \cup [2,3] $ ? It is not the union of two disjoint nonempty open sets, so it is connected?  $X$ is connected, when it cannot be divided into two disjoint nonempty closed sets.  What about $(0,1) \cup (2,3) $ ? It cannot be divided into two disjoint nonempty closed sets, so it is connected?   Maybe I don't understand what "divided" means. Google Drive storage mismatch I have a paid 100GB Google Drive plan. It is reporting that I am at 99% capacity.  According to the the storage both within the desktop and web application, I have used 90.53GB within Drive.    My Drive is mapped to my OS X filesystem, and when fully synched it reports only 61.28GB used.    So what is going on here? I need to do a cleanup but cannot account for the 30GB difference. The strongest player in the game is a close ally of mine and we each founded and follow of one of the strongest two religions in the game, with little cross-over between religions within our territories.  I've just spotted that he has a Great Prophet approaching my territory. According to the Civopedia they are powerful at spreading religion, and I'd rather not have a huge hit to the followers of my religion in my cities.  How can I prevent another players Great Prophet from damaging the religion in my cities, preferably without causing a major diplomatic incident. I have an external USB 3 disk drive (2TB capacity) that is most likely going to be moved from machine to machine. The disk has a GUID partition table and an ext4 partition. I am unable to write to the disk unless I elevate the process (sudo).  As of now I am thinking of trying one or both of the following and would like to know the cons of each -   chmod 777 /mnt/externalDrive chown nobody:nogroup /mnt/externalDrive   If I give 777 permission and user1 (UID:1005) writes to it and I later move the disk to another computer where user7 is UID:1005, what happens? Does user7 become the owner of the file on that computer? It seems to me that I will periodically have to run chown -R nobody:nogroup /mnt/externalDrive on the disk.  Is any of what I am considering an obvious bad practice? The disk will most likely contain videos, music and pictures none of it need to be protected like some financial data. I would like to understand a couple of fact on maximum likelihood estimators (MLEs) for logistic regressions.   Is it true that, in general, the MLE for logistic regression is biased? I would say "yes". I know, for example, that sample dimension is related to the asymptotic bias of MLEs.   Do you know any elementary examples of this phenomenon? If the MLE is biased, is it true that the covariance matrix of the MLEs is the inverse of the Hessian of the maximum likelihood function?   edit: I have met this formula quite often and without any proof; it seems a quite arbitrary choice to me.