I need a key-value pair and I need to iterate over it, but I need to remove the &amp; from the last iteration.  My key-value Map object is defined as:  private Map&lt;String, String&gt; additionalAttributes = new HashMap&lt;String,String&gt;();   I perform my iteration as such:  for(Entry&lt;String,String&gt; i : additionalAttributes.entrySet()) {     attributes += i.getKey() + "=" +i.getValue() + "&amp;"; }   Is there any way I can determine if the current entry i is the last entry in the map? The map will vary in size and contents each time it's run so I need a dynamic solution.
While working in a Java app, I recently needed to assemble a comma-delimited list of values to pass to another web service without knowing how many elements there would be in advance. The best I could come up with off the top of my head was something like this:  public String appendWithDelimiter( String original, String addition, String delimiter ) {     if ( original.equals( "" ) ) {         return addition;     } else {         return original + delimiter + addition;     } }  String parameterString = ""; if ( condition ) parameterString = appendWithDelimiter( parameterString, "elementName", "," ); if ( anotherCondition ) parameterString = appendWithDelimiter( parameterString, "anotherElementName", "," );   I realize this isn't particularly efficient, since there are strings being created all over the place, but I was going for clarity more than optimization.  In Ruby, I can do something like this instead, which feels much more elegant:  parameterArray = []; parameterArray &lt;&lt; "elementName" if condition; parameterArray &lt;&lt; "anotherElementName" if anotherCondition; parameterString = parameterArray.join(",");   But since Java lacks a join command, I couldn't figure out anything equivalent.  So, what's the best way to do this in Java?
Proper display of fractions Installing File Geodatabase (*.gdb) support in QGIS? I have spent around 2 days to find the way to open GDB (Esri geodatabase) in QGIS (or any other open source software) but still without success.  I have downloaded the newest OSGeo4W installer and tried the setup - express desktop install - all packages, as well as advanced install incl gdal-filegdb.  Can you describe a more detailed procedure, including installation and how to open .gdb in QGIS (OSGeo4W installation)? If $f(x)$ and $g(x)$ are two periodic functions, that is, $f(x+T_1)=f(x)$ and $g(x+T_2)=g(x)$ for every $x \in \Bbb R$. Now that $\displaystyle\lim_{x\to\infty}(f(x)-g(x))=0$.  Conjecture: $f(x) \equiv g(x)$. How can I diagnose and repair missing drive space? I have a small ext3 / partition on a 2T drive which appears to have a discrepancy in its free space. How can I determine what is causing it and how it can be fixed.   After trying everything I could think of, I forced a fsck on boot which didn't have any affect.  I have other systems configured identically which don't exhibit this condition.  # df -h / Filesystem            Size  Used Avail Use% Mounted on /dev/sda1             9.7G  8.9G  318M  97% /  # du -shx --max-depth 1 / 5.2G    /  # lsof | awk 'BEGIN {t=0} /(deleted)/ {t+=$7} END {print t}' 0  # tune4fs -l /dev/sda1 | grep -E 'state|Free|Reserve|size|Inode' Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super large_file Filesystem state:         clean Inode count:              2621440 Reserved block count:     131029 Free blocks:              212317 Free inodes:              2487281 Block size:               4096 Fragment size:            4096 Reserved GDT blocks:      639 Inodes per group:         32768 Inode blocks per group:   1024 Reserved blocks uid:      0 (user root) Reserved blocks gid:      0 (group root) Inode size:               128   Edit:  fsck says the partition is 2% non-contiguous.  For comparison to du above (sparseness):  # du -hxs --apparent-size / 4.9G    / I noticed that if I run ls -F on a directory, some of the entries have a * or a @ after them.   spuder@ubuntu:~$ ls -F /sbin acpi_available*   getpcaps*           lvmconf*                 ntfscp*        start-stop-daemon* agetty*           getty*              lvmdiskscan@             ntfslabel*     status@ alsa*             halt@               lvmdump*                 ntfsresize*    stop@ alsactl*          hdparm*             lvmsadc@      spuder@ubuntu:~$ ls -F ~ daq-0.6.1/  examples.desktop       noname-cache.lib  snort-2.9.1/   Templates/ Desktop/    jpgraph-1.27.1/        noname.sch        snortfiles/    Ubuntu One/ Documents/     According to the ls man pages   spuder@ubuntu:~$ man ls ... -F, --classify   append indicator (one of */=&gt;@|) to entries ...   I'm guessing that @ means symbolic link,     What do these other indicators mean ( */=&gt;@| )  ? SQL Server: Cannot insert an explicit value into a timestamp column Does standard c library provides linked list etc. data structures? List of IP addresses/hostnames from local network in Python How can I get a list of the IP addresses or host names from a local network easily in Python?  It would be best if it was multi-platform, but it needs to work on Mac OS X first, then others follow.  Edit: By local I mean all active addresses within a local network, such as 192.168.xxx.xxx.  So, if the IP address of my computer (within the local network) is 192.168.1.1, and I have three other connected computers, I would want it to return the IP addresses 192.168.1.2, 192.168.1.3, 192.168.1.4, and possibly their hostnames. Expectation of a function of a random variable from CDF Is it possible to calculate the expectation of a function of a random variable with only the the r.v.'s CDF? Say I have a function $g(x)$ that has the property $\int_{-\infty}^{\infty}g(x)dx \leq \infty $ and the only information I have about the random variable is the CDF.  For example, I have a scenario where there are three timers that can be modeled as exponential random variables $X_1,X_2,X_3$ with rate parameters $\lambda_1,\lambda_2,\lambda_3$ respectively. For each moment in time I earn a reward according to some reward function $g(x)$. That is, my reward for waiting until time $t$ can be written as $\int_0^tg(x)dx$. However, $g(x)$ experiences diminishing returns so the the marginal reward received from waiting one second at $t=0$ is greater than one second at say $t=27$. This 'game' ends when one of two things happens. Either both timers $X_1$ or $X_2$ must ring or timers $X_1$ or $X_3$ must ring. I'm trying to find the expected reward of playing this game.  Currently I can calculate the the CDF of the random variable modeling the time until the game ends, but I dont know how to use this information to when what I really need is reward associated with this time.  So far I have the additional random variables: $$ W_{12}=\max(X_1,X_2) \quad W_{13}=\max(X_1,X_3) \quad Z=\min(W_{12},W_{13})$$ Also let $F_i(x), i\in \{1,2,3\}$ denote the CDF of $X_i$ The CDF of $Z$, can be written as: $$F_Z(t) = F_1(t)F_2(t) + F_1(t)F_3(t) - F_1(t)F_2(t)F_3(t)$$  I know when a random variable takes on non-negative values, you can use a shortcut to calculate the expectation using the CDF. That is, $E[X] = \int_0^\infty F(X\geq x)dx$. Is there something similar I could use for a function of a random variable, or is it necessary to compute the pdf of $Z$ first to compute $\int_0^\infty g(t)f_z(t)dx$ Question mark for sentence which starts with a question but doesn't end with one I'm basically looking at sentences which start with a question, and end with an explanation to it. But there may be more instances of a similar structure. Sample sentence :      Can you book a room in advance, because otherwise we'd be in trouble   Should this sentence end with a period or a question mark?  PS: I read the apparently similar question  but the sentence structure there is different from what I'm looking for.  Edit: I just discovered that this question is a duplicate. A resolved question already  exists:   But i do like the explanations here better. C array setting of array element value beyond size of array Can you make a non-polar electrolytic capacitor out of two regular electrolytic capacitors? There was some discussion on this question        which I don't see as being conclusively resolved:   "turns out that what might LOOK like two ordinary electrolytics are not, in fact, two ordinary electrolytics." "No, do not do this. It will act as a capacitor also, but once you pass a few volts it will blow out the insulator." 'Kind of like "you can't make a BJT from two diodes"' "it is a process that a tinkerer cannot do"   So is a non-polar (NP) electrolytic cap electrically identical to two electrolytic caps in reverse series, or not?  Does it not survive the same voltages?  What happens to the reverse-biased cap when a large voltage is placed across the combination?  Are there practical limitations other than physical size?  Does it matter which polarity is on the outside?  I don't see what the difference is, but a lot of people seem to think there is one.  Summary:   As posted in one of the comments, there's a sort of electrochemical diode going on:     The film is permeable to free electrons but substantially impermeable to ions, provided the temperature of the cell is not high. When the metal underlying the film is at a negative potential, free electrons are available in this electrode and the current flows through the film of the cell. With the polarity reversed, the electrolyte is subjected to the negative potential, but as there are only ions and no free electrons in the electrolyte the current is blocked. —    Normally a capacitor cannot be reverse-biased for long, or large currents will flow and "destroy the center layer of dielectric material via electrochemical reduction":     An electrolytic can withstand a reverse bias for a short period, but will conduct significant current and not act as a very good capacitor. —    However, when you have two back-to-back, the forward-biased capacitor prevents a prolonged DC current from flowing.  :     For circuit positions when reverse voltage excursions are unavoidable,   two similar capacitors in series connected “back to back” ... will create a   non-polar capacitor function ... This works because almost all the circuit voltage   is dropped across the forward biased capacitor, so that the reverse   biased device sees only a negligible voltage.   :     The oxide dielectric construction that is used in tantalum capacitors   has a basic rectified property which blocks current flow in one   direction and at the same time offers a low resistance path in the   opposite direction. What does 'super' do in Python? - difference between super().__init__() and explicit superclass __init__() What's the difference between:  class Child(SomeBaseClass):     def __init__(self):         super(Child, self).__init__()   and:  class Child(SomeBaseClass):     def __init__(self):         SomeBaseClass.__init__(self)   I've seen super being used quite a lot in classes with only single inheritance. I can see why you'd use it in multiple inheritance but am unclear as to what the advantages are of using it in this kind of situation. How do I stop orca from starting up on login? Orca keeps starting up after system starting, and I'm not able to find it in "Startup Applications".  How to stop it? Run cURL commands from Windows console Is there a way to install cURL in windows in order to run cURL commands from the command prompt? I know that to better balance paragon and epic level players against similar level monsters, WotC changed the math used for monsters for MM3, and I believe that they changed some of the types of powers they gave monsters.   If I want to update monsters from MM1 or MM2 to be in line with MM3 era monsters, what changes should I make? How to connect nodes to node group inputs and outputs in python? $\int_0^{\pi/2}\ln(\sin(x))$? From this paper:     Shouldn't $du$ be $dt$? And also how do you get from that line to the final result if $du$ is not $dt$? Why don't custom upstart job names tab complete in the service command? How do I bake a texture using Cycles bake I created a interior scene and  i don't know how to bake a texture using cycles bake.