I'm having the problem, that i'm comparing 3 substrings    a.substring(0,1)   a.substring(1,2)  and  a.substring(2,3)     and I set a = "XXX" and when I print the substrings, they all say X but when i compare them like this:   if(a.substring(0,1) == a.substring(1, 2) &amp; a.substring(1, 2) == a.substring(2, 3)) {      System.out.println("Hello");  }   it does nothing. I checked if I'm using the If clause wrong but when I tested this:   System.out.println(a.substring(0,1) == a.substring(1,2));   It returned false too.  I'm currently using Java in Eclipse and I even defined my a variable manually instead of using my function, I planned on using before, for testing.  I'm happy if anyone could help
I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?
How to fill down in Numbers without dragging? Why do you cast downvotes on answers? Solvability and reducibility of a polynomial in a "chain" of finite fields A logic puzzle involving a balance. Possible Duplicate:          You have 12 balls and you know that they all weigh the same except for 1 which is heavier or lighter than all the others (you don't know which though). How can you make sure you know which ball is the heaviest/lightest in only 3 weighings?  The way I approached it was to split up the 12 balls into three sets of 4 and weigh two of the sets. If the sets balanced the scale, then I know the ball I am looking for must be in the set of 4 balls not weighed, else, I disregard said set and arbitrarily choose the heaviest set of 4 (as opposed to choosing the lightest set). I split the heaviest set of 4 balls into 2 and weigh that... etc.  Repeating this process until all 3 tries have been "used up", even if everything just so happened to be in your favor (the arbitrary choice you have in choosing the heaviest or lightest set happens to be the correct choice) in the end you still end up having to choose between 2 balls. A 50% chance is good, but I am wondering, is there a way to make sure 100%? I know that editing the boot options line and adding 'nomodeset' solves the problem of my laptop during LiveCD mode, what I don't know is how to set it at boot up through Grub2 after I've installed Ubuntu.  So, my question is; how do I set nomodeset before I boot into Ubuntu? Show that if $f: \mathbb{R} \to \mathbb{R}$ is a continuous injective map, then it is strictly monotonic.    Could someone give me a proof for this? I have the intuition for why it's true - I'm just having trouble expressing that intuition in a rigorous manner. Basically consider two points $x_1, x_2 \in \mathbb{R}$. By the problem statement, $f$ is continuous on $[x_1, \, x_2]$. WLOG, assume that $f$ is strictly increasing. It there exists a point where it is not increasing, then $f$ hits a value twice, and it's not injective. I have been trying but its not working.  but if i try   &lt;?php echo do_shortcode("[mimo]"); ?&gt; &lt;?php echo do_shortcode("[mibaby]"); ?&gt;   it will work fine.  But to apply it in post content using [mimo] [mibaby]  it won't work.  Here is the Functions i am using...  function wpb_custom_new_menuw() {   remove_filter( 'the_content', 'wpautop' ); } add_shortcode('mibaby', 'wpb_custom_new_menuw');    function wpb_custom_new_menu() {   remove_filter( 'the_excerpt', 'wpautop' ); } add_shortcode('mimo', 'wpb_custom_new_menu'); An example of a group such that $G \cong G \times G$ I was trying to find an example such that $G \cong G \times G$, but I am not getting anywhere. Obviously no finite group satisfies it. What is such group? Hardware issue on iMac, flashing question mark I have an iMac 2008/2009 issue and recently the computer would not boot and I would get a flashing question mark. Ran through all the usual steps, try boot in safe mode, flash RAM,  try single user for fdisk, put in OS disk and boot from CD, etc... No dice.   Replaced the hard drive and put the OS disc in the system, press and hold option. (holding C didn't work) I can see the OS disk but when I click on it the system will act like it is going to run and then freeze. The best I got was the OS X disc that changed the screen to dark grey and told be the system had to restart.  Purchased a usb mount for an external hard drive. Was able to mount the old hard drive to a laptop and run disk utility. Everything checked out.  At this point I am pretty sure it isn't the hard drive.   Any other hard ware items this can point too? My iMAC can also "see" the hard drive (and the recovery partition) when connected via the USB and I hold "option" on start up. But it crashes when trying to boot from either.  I am going to take out and re-install the RAM for giggles but I am not sure what else to do.   Ideas are welcome. In  video, he uses a command block to give him jump boost while he is wearing his Boots of Leaping.  I am trying to imitate this for a multiplayer map I am making. Wearing golden boots called "Stealth Boots" is supposed to give that player invisibility. I am using this command:  /effect @a[Inventory:[{Slot:100b,tag:{display:{Name:"Stealth Boots"}}}]] 14 30000 200  I do know that in the video he is using a /testfor command, but since I'm making a multiplayer map in order to use this technique I'd have to define a scoreboard variable for each player - and even then, the players would be finite. Thus, I want to be able to use the command DIRECTLY.  When I use that command, it either says "That player cannot be found" or "The entity UUID provided is in an invalid format" - the former of which I'm familiar with; the later I've barely ever seen before.  So, my method doesn't seem to work - how do I fix it? I am stuck with the proof of below expression;  "If F is an infinite field, then no infinite subgroup of F* (the multiplicative group of F) is cyclic."  anyone can help? Apple Loops Copyright Why copy constructor not invoked here Let $A$ be a nonempty and bounded below, and define $B= \{b\in \mathbb{R}: b$ is a lower bound for $A\}$. Show sup$B$ = inf$A$.   So far I have: Let $A$ be nonempty and bounded below. This implies $\exists l \in A, \forall a \in A, l\leq a$ and $l =$ inf$A$. Let $B = \{b\in \mathbb{R}: b$ is a lower bound for $A\}$ and let $M=$ sup$B$. This implies $\exists b\in B, \forall b \in B, b\leq M$. By definition of $B$, we know inf$A \in B$. Since $b\leq$ sup$B$, with sup$B$ the largest element in $B$, we have inf$A \leq M =$ sup$B$, so inf$A \leq$ sup$B$.  I realize I have to prove that sup$B \leq$ inf$A$ to get that sup$B$=inf$A$. I am having trouble doing so.   Part B: Use (a) to explain why there is no need to assert that greatest lower bounds exist as part of the Axiom of Completeness. How to clear the interpreter console? Like most Python developers, I typically keep a console window open with the Python interpreter running to test commands, dir() stuff, help() stuff, etc.  Like any console, after a while the visible backlog of past commands and prints gets to be cluttered, and sometimes confusing when re-running the same command several times.  I'm wondering if, and how, to clear the Python interpreter console.  I've heard about doing a system call and either calling cls on Windows or clear on Linux, but I was hoping there was something I could command the interpreter itself to do.  Note: I'm running on Windows, so Ctrl+L doesn't work. error: file '/grub/i386-pc/normal.mod' not found. grub rescue&gt;   What can I do? I just sit and stare at it.   I found my old netbook (Dell Inspiron 1010) which I have not used for about four years. I replaced Windows XP with Ubuntu 12.10. I used my bootable USB drive. I installed and rebooted. I got the message that normal.mod is not found.   What should I do? Type exit, reboot, or quit? Should I re-install? What is the most elegant proof of the Pythagorean theorem? The  is one of the most popular to prove by mathematicians, and there are  (including one from ).    What's the most elegant proof?  My favorite is this graphical one:    According to cut-the-knot:     Loomis (pp. 49-50) mentions that the   proof "was devised by Maurice Laisnez,   a high school boy, in the   Junior-Senior High School of South   Bend, Ind., and sent to me, May 16,   1939, by his class teacher, Wilson   Thornton."      The proof has been published by Rufus   Isaac in Mathematics Magazine, Vol. 48   (1975), p. 198. How do you judge the quality of a journal? Adding other css files to wp_head Annuity notation in LaTeX How do you write this in LaTeX: