Changing String to Date
What is a NullPointerException, and how do I fix it?
Is there a gender-neutral pronoun that can replace “his” or “her”? This post has two parts: (a) a question and (b) a proposal.   (a) Often, particularly while writing technical papers or user's manuals, I have come across a situation where I need to say:      A user of this software may not need to use it from his personal computer. He can use it from a phone or even from his tablet.   I have seen many authors use female pronouns (i.e. “she” and “her”), but lately this trend seems to have ebbed somewhat.   I, and (I suspect) many other authors, do not want to use passive voice to avoid this.   Is there a gender-neutral way to describe the same situation?   (b) If there is none, I would like to propose using “ze” (for “he” or “she”) and “zir” (for “his” or “her”, rhyming with “fir”) as gender-neutral pronouns. I want to know how you feel about these words. From the Cracks in time and space story arc it's known that if a TARDIS is blown up (possibly while in the Time Vortex) it rips creation itself apart. Also, from the Stolen Earth / Journey's End we learn the Daleks' masterplan which is subjugating creation itself via destroying it with the Reality Bomb (unfading Z-neutrino energy radiation).  In the Last Great Time War all sorts of temporal weapons were used and it's known that Daleks have the ability of time travel as well. Why didn't they use the Time Vortex back then to win the war once and for all via detonating a TARDIS while inside? Calculate probability (area) under the overlapping area of two normal distributions Is there a tag in HTML that will only display its content if JavaScript is enabled? I know &lt;noscript&gt; works the opposite way around, displaying its HTML content when JavaScript is turned off. But I would like to only display a form on a site if JavaScript is available, telling them why they can't use the form if they don't have it.  The only way I know how to do this is with the document.write(); method in a script tag, and it seems a bit messy for large amounts of HTML. Exactly half of the elements of $\mathcal{P}(A)$ are odd-sized Let $A$ be a non-empty set and $n$ be the number of elements in $A$, i.e. $n:=|A|$.  I know that the number of elements of the power set of $A$ is $2^n$, i.e.  $|\mathcal{P}(A)|=2^n$.  I came across the fact that exactly half of the elements of $\mathcal{P}(A)$ contain an odd number of elements, and half of them an even number of elements.  Can someone prove this? Or hint at a proof? "Your Sites" in Android left sidebar shown in unpredictable order Now that I have Firefox 49 or higher, how do I watch Netflix? Just got the Firefox 49 update (yay!)  But Netflix still wants to install Silverlight (boo!)  How can I watch Netflix in Firefox, as ? How can I iterate, loop, process, or otherwise do something, with each element from a comma separated list of things?  This question       , and the are already lots of very good answers everywhere. However I think it would also be valuable to have a single reference point where all such alternative techniques are explained in detail, with their advantages and disadvantages discussed.  All of plain-TeX, LaTeX, LaTeX3, LuaTeX, Context, etoolbox, pgffor, etc. answers are invited. Please consider explaining, for example:   How does the command/method deal with whitespace around items? How does the command/method deal with empty/missing items? (e.g. a,b,,c) How does the command/method deal with a trailing comma? Can the command/method work of a list stored on a macro? Is each iteration evaluated globally or on a local group? (i.e., if a command is defined during an iteration, does the command survive the loop?) Do items get expanded or somehow mangled before being processed? What about lists where items are key=value or some other kind of pairs? Does the method work for lists separated with something other than a comma? Any other thing I should know before deciding to use this method? Software Tester Skill Matrix with Levels I would like to know if there's a standard Skill set for Skill Matrix for a Software Tester of different levels, like for example, what are the skills needed for an Entry level tester as well as what technologies and responsibilities he needs. And for the Mid Level tester and Senior Level as well.  Note that I am working in a company who designs and develops websites. Sheafs and closed immersion Why is jumping into water from high altitude fatal? Can an LC oscillator be used to generate visible light? The LC oscillator is most commonly used to generate radio waves for practical use and the frequency $\omega$ of the LC oscillator equals that of the electromagnetic wave so produced. So, can they in principle be used to emit visible light?  The frequency of visible light is on the order of a few hundred terahertz, and the frequency of an LC oscillator is   $$\omega = \frac{1}{\sqrt{LC}}$$  I admit, the  product $LC$ does become very small (on the order of $10^{-30}$) when the numbers are plugged in, but making an inductor and a capacitor with small values isn't difficult, is it? Render just part of a final image from Cycles? I'm using an older Nvidia chip that hates running viewport renders, and I need to check if changes to the materials on a few objects not far from the center of my scene are (I'm rendering a floorplan with an orthographic camera from above, so I'm looking down on objects and want to check if the displacement materials are working correctly).  Is there any way to select a bit of the image and have it render first or without having to render the rest of the image? I'm aware that you can tell the image to render from an edge, but my stuff's about equidistant from either side of the scene. House address is not listed on Google Maps When I search for my address on Google Maps it cannot be found which means I can't order takeaway etc.  Is there a way of adding my address to Google Maps or even add a street address?  I want the address to be publicly available so others can search it. I need to render a model on a transparent background. The models have a light source so they should be casting a shadow on a surface (the XY plane). The purpose for this is to overlay the rendered images (out of blender) on an image of the actual surface, so I want to generate the render including a semi-transparent shadow.  I don´t have any problem rendering the models on transparent background, but I can not make a shadow appear. I tried adding a surface below the model so the shadow can fall on it, but now there's the problem of keeping the surface from rendering.  How can I render the shadow on a transparent background? Suppose that I create Material001  and Material002  in Material Properties and set them to some color. Can I use this 2 items in other buttons like Texture Properties, Object Data Properties etc. ? Where and how do I intertwine them with this button ? Let $q \in \mathbb C$, $\|q\|=1$ and $q^n \neq 1, \forall n \in \mathbb N$. Show that $\{q^n: n \in \mathbb N\}$ is dense in $S^1$ Let $q \in \mathbb C$, $|q|=1$ and $q^n \neq 1, \forall n \in \mathbb N$. Show that $\{q^n:  n \in \mathbb N\}$ is dense in $S^1$.  My attempt: As $(q^n)$ is limited, there is subsequence $(q^{n_j})$ convergent. So given $\epsilon &gt; 0, \exists j_0 \in \mathbb N, \quad |q^{n_j} - q^{n_k}| &lt; \epsilon, \quad \forall j,k \geq j_0$. Supose that $n_j &gt; n_k$, then  $|q^{n_j} - q^{n_k}| = |q^{n_k}||q^{n_j - n_k} - 1| = |q^{n_j - n_k} - 1| &lt; \epsilon, \quad \forall j, k \geq j_0$. So, there is a subsequence of $(q^n)$ that converges to $1$.  Using this fact, how can I ensure that for all $w \in S^1$ there is a subsequence of $(q^n)$ that converges to  $w$? Trigger a button click with JavaScript on the Enter key in a text box I have one text input and one button (see below). How can I use JavaScript to trigger the button's click event when the Enter key is pressed inside the text box?  There is already a different submit button on my current page, so I can't simply make the button a submit button. And, I only want the Enter key to click this specific button if it is pressed from within this one text box, nothing else.  &lt;input type="text" id="txtSearch" /&gt; &lt;input type="button" id="btnSearch" value="Search" onclick="doSomething();" /&gt; Relationship between gamma and chi-squared distribution If $$Y=\sum_{i=1}^{N}X_i^2$$ where $X_i \sim \mathcal{N}(0,\sigma^2)$, i.e. all $X_i$ are i.i.d. normal random variables of zero mean with same variances, then $$Y \sim \Gamma\left(\frac{N}{2},2\sigma^2\right).$$  I know the chi-squared distribution is a special case of the gamma distribution, but could not derive the chi-squared distribution for random variable $Y$. Any help, please? Finite groups with exactly one maximal subgroup