String concatenation showing unexpected behavior
How do I compare strings in Java?
Plot draws list of curves in same color when not using Evaluate I want to have more than one user logged on at the same time, on the same computer. Each user should have a full X session. It is easy enough to log in to multiple concurrent non-X Linux terminals, but I want the X factor. Maybe I've missed something, but I only see a Main Menu option to Log out of the current user, and nothing for Switch User. Is there a simple way to do this? Integral Inequality $|f''(x)/f(x)|$ Let $f$ be a $C^2$ function in $[0,1]$ such that $f(0)=f(1)=0$ and $f(x)\neq 0\,\forall x\in(0,1).$ Prove that  $$\int_0^1 \left|\frac{f{''}(x)}{f(x)}\right|dx\ge4$$ While trying to ask a question, I got the error message     This question body does not meet our quality standards. Please make sure that it completely describes your problem - including what you have already tried - and is written using proper grammar.    Why am I getting this message? What can I do to get the system to accept my question? Can you be more specific? What are good resources on how to ask high-quality questions?      For more information, see  in the . Man undergoes radical surgery to research aliens Removing intercept from GLM for multiple factorial predictors only works for first factor in model I am running a binomial logistic regression with a logit link function in R. My response is factorial [0/1] and I have two multilevel factorial predictors - let's call them $a$ and $b$ where $a$ has 4 factor levels  $(a_1,a_2,a_3,a_4)$ and $b$ has 9 factor levels $(b_1,b_2,\dotsc,b_9)$. Therefore:  mod &lt;- glm(y ~ a + b, family = binomial(logit), data=pretend) summary(mod)   The model output would then show all the information about the model as well as the coefficients.  There is a factor level for both a and b missing (a1 and b1) from the summary output. I understand that it is constrained in the "intercept" of the model. I have read that if I want to remove the intercept term and see the estimates for those factor levels I can just add -1 to the model formula, i.e.:  mod2 &lt;- glm(y ~ a + b - 1, family=binomial(logit), data=pretend) summary(mod2)   In the new model (mod2) the intercept term is then gone and variable a's factor-level a1 is given amongst the list of coefficients. But, variable b's factor-level b1 is still missing and given that there is no intercept term anymore, how can I interpret the odds-ratio for that factor level then?  Could someone please explain to me how to get the coefficient for b1 too and why this is happening? Book about classical mechanics Calculating centroids of polygon using ArcPy? I am trying to calculate the centroids of a polygon and add the x- and y-coordinate to their respective fields:  arcpy.env.workspace = r"C:/..."  input_fc = "shapefiles/precincts_v.shp" arcpy.AddField_management(input_fc, "X", "DOUBLE") arcpy.AddField_management(input_fc, "Y", "DOUBLE")  arcpy.CalculateField_management(input_fc, "X", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[0]", "PYTHON")  arcpy.CalculateField_management(input_fc, "Y", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[1]", "PYTHON")    but I an invalid syntax error. Where is the mistake?  Edit: exact error message  Traceback (most recent call last):   File "C:\Users\mquentel\Dropbox\PLSS\CA voting data\Python\CONSTRUCT_merge_voting_and_census.py", line 17, in &lt;module&gt;     arcpy.CalculateField_management(input_fc, "X", "!SHAPE.CENTROID@DECIMALDEGREES!.split()[0]", "PYTHON")   File "C:\Program Files (x86)\ArcGIS\Desktop10.4\ArcPy\arcpy\management.py", line 3360, in CalculateField     raise e ExecuteError: ERROR 000539: SyntaxError: invalid syntax (&lt;expression&gt;, line 1) Failed to execute (CalculateField). This is in Windows, but answers for other operating systems can be handy to others.  Most guides say something to the effect of "hold down the Alt key and type in the code on the keypad".  This works fine for decimal codes (like 65 for 'A'), but not for  codes (like  for 'A').  Some applicatons provide other facilities that will allow hexadecimal Unicode character codes to be typed and then transformed.  Word allows you to type the code (such as 200f) and then convert it to Unicode by typing Alt-X.  I'm looking for a general method of doing this that will work with the standard input. When polynomials f(x) and f'(x) are relatively prime, f(x) has no repeated roots. Why? The problem is to show that a polynomial $f(x) \in F[x]$ (F is a field) has no repeated roots if and only if f(x) and f'(x) (the derivative of f(x)) are relatively prime. I've managed to prove one direction of this equivalence (if there are no repeated roots, f(x) and f'(x) are relatively prime), but the other one gives me headaches... can anyone help out? How to find normal and lognormal moments, given partial information? $Y=\ln(X)$. $X$ is lognormal and $Y$ is normal. If all I know is the arithmetic mean of $Y$ and the standard deviation of $X$. What is the formula to calculate the arithmetic mean of $X$ and the standard deviation of $Y$? Which of these two is more correct and why?   The sun shines on my little tree. The sun shines upon my little tree.   From what I've read in dictionaries both are acceptable, however I would like to know if there are subtleties that might arise due to, for example, the context. This problem comes from , who do not rigorously demonstrate (in their solution key) that the statistic is not sufficient.  Let $X_1,\dots,X_n$ be a random sample from a population with PDF $f(x|\theta)=\theta x^{\theta-1} \cdot 1_{\{x\in(0,1)\}}$ for $\theta&gt;0$. Show that $\sum_i X_i$ is not sufficient for $\theta$.  If you write out the PDF $p(\vec{x}|\theta)$ of the random sample, it is clear by the factorization theorem that $\prod_i X_i$ or $\sum_i \log(X_i)$ are sufficient for $\theta$; the PDF $p$ also suggests $\sum_i X_i$ is not sufficient for $\theta$. However, to rigorously demonstrate this, we need to analyze $p(\vec{x},\theta)/q(T(\vec{x},\theta)$, where $p$ is the distribution of sample $\vec{x}$, $q$ is the distribution of the statistic $T(\vec{X})=\sum_i X_i$. But finding the distribution of $T(X)=\sum_i X_i$ seems impractical. I have observed that $f$ is the PDF of a Beta($\theta$,1) distribution, but checking online, the distribution of the sum of Beta random variables doesn't appear to have a closed form. Are there any alternative routes (e.g., showing there is no factorization involving $T(\vec{X})$)? Did C&amp;B leave out a full explanation that $\sum_i X_i$ is not sufficient because none actually exist? How to ask a smart question The title of  of  is, "Is it posible [sic]?"  This doesn't provide any information at all. It should be mandatory for everyone asking questions on the Internet to read , which says:     Help your community learn from the question. When you field a good question, ask yourself "How would the relevant documentation or FAQ have to change so that nobody has to answer this again?" Suppose $f: \mathbb{R} \to \mathbb{R}$ is a continuous function which is 1-1, then does $f$ map Borel sets onto Borel sets? Is there any hint of of the first Wizarding War being an international event? Is there any hint that the MoM or anywhere else got support in combating voldemort the first time around? Or is everything completely UK-centric?  I can't remember anyone in the second war being specifically sent from europe to help, even though we see international wizards in book 4. But I don't think all the events of the first war are covered in the books.  So are other bodies like the MoM involved in the first war, or was it isolated in the UK? How do I set up my LaTeX document to enable me to cite from my BibTeX bibliography? This may be an overly simplistic question but please bear with me...  I have a BibTeX bibliography containing all of my references, set up using BibDesk. I am now trying to cite these references in my LaTeX documents. Following the advice on the LaTeX wikibooks page, I have included the following lines into my LaTeX document...  \bibliographystyle{plain} \bibliography{/Users/Graeme/Documents/References/BIBliography.bib}   ... where BIBliography is my .bib file, created in BibDesk.  Unfortunately, when I cite something in the document, using \cite{citekey} and typeset the document, the log tells me that there were undefined references. In the .pdf that is produced, there is a [?] where the references should be.  Am I doing something wrong? Do I need to store my .bib for in a particular location? I know there can be some errors that mean you need to typeset the document several times, but I have tried countless times to no avail.  I would be very grateful if someone could help out. Is it possible to accept the alternative hypothesis? I'm aware of several related questions here (e.g., , ) but I don't know the definitive answer for my question below.  Suppose a hypothesis test where we want to test whether a coin is fair or not. We have two hypotheses:  $H_0: p(head)=0.5$  $H_1: p(head)\neq0.5$  Suppose we use 5% significance level, there are two possible cases:   When we obtain the data and find that the p-value is less than 0.05, we say "With significance level 5%, we reject $H_0$."  p-value is greater than 0.05, then we say "With 5% significance level, we cannot reject $H_0$."   My question is:      In case 1, is it correct to say "we accept $H_1$"?   Intuitively, and from what I have learned in the past, I feel that "accepting" anything as a result of hypothesis testing is always incorrect. On the other hand, in this case, since the union on $H_0$ of $H_1$ covers the whole "space", "reject $H_0$" and "accepting $H_1$" look exactly the same to me. On another thought, I can also think of the following idea, which says it is incorrect to say "we accept $H_1$":     We have an evidence strong enough to believe that $H_0$ is not true, but we may not have an evidence strong enough to believe that $H_1$ is true. Therefore, "rejecting $H_0$" does not automatically imply "accepting $H_1$"   So, what is the right answer? Cleaning wax and pesticide from apple skin I love apples. I like to eat them with skin as it has plenty of fiber in the skin. But apples are famous for wax and pesticides on the skin which I don’t want to ingest. I have read many articles on the web and suggestions for removing the wax from the surface.   These suggestions include soaking in vinegar or hot water and other methods. They suggest that soaking apples in vinegar removes the wax that can be seen in the vinegar. I have done that, but never seen any residue of wax in the vinegar.   So I have set aside a new kitchen sink Scotch-Brite scrubber for this purpose and been scrubbing the apple skin under running water before eating. I think this method should remove most of the wax and pesticides. I would like to hear your input. What is the maximum party size and the corresponding monster buffs? What is the maximum party size (if there is one) in Diablo 3?  Additionally, how much of a buff do monsters get when adding party members?     "A new ally has joined, but the minions of Hell grow stronger."