Why does the following code return an empty array as a result ([])?  $('#non-existing-id').first();   I thought that it should return null or undefined.  How can I check for the success then? I don't see anything about it in the documentation.
In Mootools, I'd just run if ($('target')) { ... }.  Does if ($('#target')) { ... } in jQuery work the same way?
Chapter number starts at 2 not 1 How can I start my chapter from "Chapter 2" instead of "Chapter 1".  I am preparing LaTeX document for each chapter. when I put \chapter{Introduction}, it produces "Chapter 1" Introduction. However I want it to be "chapter 2" Introduction instead. How to connect to Oracle as "SYS" from SQL*Plus in Java Is it possible to make the default scene fill two monitors at startup? I know how to set up the default scene by pressing Ctrl+U, but whenever I startup Blender it always fills only one of my screens, even if I set it to fill both before setting the default scene. I end up having to resize it every time I start it up. Is there a way to set this to happen by default? Knowing the interface of ubuntu and editing them Where are the files for the desktop or the interface that appears on the screen stored? And how can we edit them. How are they programmed?  What programming language is used to built the interfaces? I've noticed the following happen a few times:   A user posts a question. The question is closed as a duplicate and the usual "Possible Duplicate" links are added at the top. The user promptly removes the duplicate links, even though the question is still closed as a duplicate. (excessive use of list items =P)   Now, I could understand this behavior if there was some dispute about whether or not the question was a duplicate, and the OP were to remove the links and post reasons why they disagree with the closing. However, I've noticed this happening without any attempt to defend the question (such as ).  In my opinion, no one should be allowed to remove the "Possible Duplicate" links as long as the question is still closed as a duplicate. The links should remain for the benefit of the community, so they can navigate to the duplicate questions and either post answers there or read them over and judge if the closing was actually fair. Once/if the question is reopened the links could be edited out if one so chooses.  I guess this is part discussion, part feature request:  Could the "Possible Duplicate" links remain un-editable for as long as the question is still closed? What is a good complex analysis textbook, barring Ahlfors's? I'm out of college, and trying to self-learn complex analysis. I'm finding  text difficult. Any recommendations? I'm probably at an intermediate sophistication level for an undergrad. (Bonus points if the text has a section on the Riemann Zeta function and the Prime Number Theorem.) The ls -al command shows the following output;  -rwxrw-r--    10    root   root 2048    Jan 13 07:11 afile.exe   What are all the fields in the preceding display? Let $x,y,z>0$ and $x+y+z=1$, then find the least value of ${{x}\over {2-x}}+{{y}\over {2-y}}+{{z}\over {2-z}}$ Let $x,y,z&gt;0$ and $x+y+z=1$, then find the least value of  $${{x}\over {2-x}}+{{y}\over {2-y}}+{{z}\over {2-z}}$$  I tried various ways of rearranging and using AM > GM inequality. But I couldn't get it. I am not good at inequalities. Please help me.  I wrote $x$ as $1-(y+z)$ and I took $x+y$ as $a$ and the others as $b$ and $c$. And I am trying. Can a single player build a clan dojo? Is it possible for an one-or-two-person clan to build a dojo? If so, what are the resources involved?   I'd like to experience the whole Dojo building experience so I don't plan to join an existing Clan with a dojo already. What is a socket? In classical statistics, there is a definition that a statistic $T$ of a set of data $y_1, \ldots, y_n$ is defined to be complete for a parameter $\theta$ it is impossible to form an unbiased estimator of $0$ from it nontrivially. That is, the only way to have $E h(T (y )) = 0$ for all $\theta$ is to have $h$ be $0$ almost surely.   Is there a intuition behind this? Is seems like a rather mechanical way of defining this, I am aware this has been asked before, but was wondering if there was a very easy to understand intuition that would make introductory students have an easier time digesting the material. Interpretation of the rating of a real transformer The rating of a real transformer is 15 kVA , 2300/230-V then can we say that the primary rms is 2300 V or can we say that the secondary rms is 230 V or both.  To clarify further, suppose to solve for certain characteristics of this transformer like primary current and secondary current i use the equivalent circuit equation of the transformer referred to the primary side as:  Vp = aVs + Req*Ip + jXeq*Ip  Then what should i use for Vp or Vs in the above equation looking at the rating of the transformer.  In the above equation looking at the rating data given above is Vp= 2300 or Vs = 230 ?As mentioned earlier the transformer is mentioned to be real. \nameref breaks for star versions of section/paragraph when titlesec is loaded \nameref breaks for the star versions of section, paragraph when titlesec is loaded. I have a document that numbers paragraphs by default, but I have a few I do not want to number but would like to refer to. These are marked with \paragraph*, however, if the titlesec package is loaded at the same time, it causes nameref to display an empty string (the link box of hyperref is still visible).  MWE:  \documentclass[12pt]{article} \usepackage[sf]{titlesec} %comment this out and it works fine. \usepackage{hyperref} \begin{document} \section{Sections} \label{sec} This is \nameref{sec} \paragraph{A named Paragraph} \label{par} This is \nameref{par} \paragraph*{A starred named Paragraph} \label{par:star} This is \nameref{par:star} \end{document}   I suspect titlesec causes this defect for ALL star variants of sectioning commands but have not tested this. For me only paragraph* is relevant however a fix for all variants would be the best.  I have a hunch it might be related to this:  however this happens to go way beyond my latex knowledge and is just "magic" for me. How to run the Ubuntu ISO live image from Windows without USB or DVD?  This is a self answered question. How to backup an Android device? How can I get admin access to a Mac without knowing the current password? My Father died last year and I inherited his Mac Mini. My wife has retired and we are trying to set up the mini for her use but the changes we want to make require admin access and we do not have the information my father used to set up the machine.  Is it possible to reset the admin information without having the old information? If so, how would I go about it?   I am not a Mac user usually so any guidance will have to be pretty simple! In how many different ways can you split $10$ people into two groups with the same amount of people?  My attempt: Since the order in which you choose someone doesn't matter, I chose to calculate the combinations: $10 \choose 5$ Setting the editing style on a UITableViewCell In the Android App, if a question is closed, I won't be able to leave comments on either the question or any of its answers. There are simply no "Add Comment" buttons available anywhere if the question is closed.  See the screenshot below. The comment adding interface is simply removed on closed questions and their answers &mdash; no Reply button in the toolbar, and no Add Comment button under the question.        Occurs on Android app v1.0.50 and v1.0.51, on a HTC One running Android 4.4.3. Automatically change é to \'e – most convenient setup for accented letters? I assume this is really basic question, I'm new to LaTeX, I read a first step tutorial to get ready to write some documents but I couldn't answer my own question at this time and I really don't know where to search.  When I try to write é and compile my document, this character is not shown. I know the sequence is \'e to make it happen in the document but that is really disturbing to write.  Is there someway to write a paragraph "normally" and convert all the special chars into the LaTeX syntax? Or is there a way to allow é, à, ... writing so the compilation includes them into the document?