Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>There is lots of information about the Fibonacci Sequence on <a href="http://en.wikipedia.org/wiki/Fibonacci_number" rel="noreferrer">wikipedia</a> and on <a href="http://mathworld.wolfram.com/FibonacciNumber.html" rel="noreferrer">wolfram</a>. A lot more than you may need. Anyway it is a good thing to learn how to use these resources to find (quickly if possible) what you need.</p> <h2>Write Fib sequence formula to infinite</h2> <p>In math, it's given in a recursive form:</p> <p><img src="https://upload.wikimedia.org/math/7/6/f/76f99713cf111eb035d908228c351710.png" alt="fibonacci from wikipedia"></p> <p>In programming, <strong>infinite</strong> doesn't exist. You can use a recursive form translating the math form directly in your language, for example in Python it becomes:</p> <pre><code>def F(n): if n == 0: return 0 elif n == 1: return 1 else: return F(n-1)+F(n-2) </code></pre> <p>Try it in your favourite language and see that this form requires <strong>a lot</strong> of time as n gets bigger. In fact, this is O(2<sup>n</sup>) in time.</p> <p>Go on on the sites I linked to you and will see this (on <a href="http://mathworld.wolfram.com/images/equations/FibonacciNumber/NumberedEquation6.gif" rel="noreferrer">wolfram</a>):</p> <p><a href="https://i.stack.imgur.com/SPYOU.gif" rel="noreferrer"><img src="https://i.stack.imgur.com/SPYOU.gif" alt="Fibonacci Equation"></a></p> <p>This one is pretty easy to implement and very, very fast to compute, in Python:</p> <pre><code>from math import sqrt def F(n): return ((1+sqrt(5))**n-(1-sqrt(5))**n)/(2**n*sqrt(5)) </code></pre> <p>An other way to do it is following the definition (from <a href="http://en.wikipedia.org/wiki/Fibonacci_number" rel="noreferrer">wikipedia</a>):</p> <blockquote> <p>The first number of the sequence is 0, the second number is 1, and each subsequent number is equal to the sum of the previous two numbers of the sequence itself, yielding the sequence 0, 1, 1, 2, 3, 5, 8, etc.</p> </blockquote> <p>If your language supports iterators you may do something like:</p> <pre><code>def F(): a,b = 0,1 while True: yield a a, b = b, a + b </code></pre> <h2>Display startNumber to endNumber only from Fib sequence.</h2> <p>Once you know how to generate Fibonacci Numbers you just have to cycle trough the numbers and check if they verify the given conditions.</p> <p>Suppose now you wrote a f(n) that returns the n-th term of the Fibonacci Sequence (like the one with sqrt(5) )</p> <p>In most languages you can do something like:</p> <pre><code>def SubFib(startNumber, endNumber): n = 0 cur = f(n) while cur &lt;= endNumber: if startNumber &lt;= cur: print cur n += 1 cur = f(n) </code></pre> <p>In python I'd use the iterator form and go for:</p> <pre><code>def SubFib(startNumber, endNumber): for cur in F(): if cur &gt; endNumber: return if cur &gt;= startNumber: yield cur for i in SubFib(10, 200): print i </code></pre> <p>My hint is to <em>learn to read</em> what you need. Project Euler (google for it) will train you to do so :P Good luck and have fun!</p>
    singulars
    1. This table or related slice is empty.
    1. POHow to write the Fibonacci Sequence?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USTony Edgecombe
    1. USAndrea Ambu
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to write the Fibonacci Sequence?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COYou need to use a while loop, not map. Try to figure it out on your own, then come back with the code if you can't do it. I'm not lazy (the code is shorter than this comment). I'm doing that for you, try it out with the "while" hint ;) If you have problem with that come back again ;)
      singulars
      1. PO
      1. USAndrea Ambu
    2. COI'm back, lol. I got rid of the map(range) function and am using only a range(startNumber, endNumber) function. Now the problem I have is where to use the while statement. I try at the beginning of the function but of course there is a billin an done lines of error. Where should I be putting it? Thx
      singulars
      1. PO
      1. USSD.
    3. COTry to do, by hand, an example of input-output of your program (with a short range). Try then to figure out where your program is wrong. Try to convert the "by-hand method" in code. This is for exercise, to learn. I could put down two lines of code but I don't think you'll learn anything from them.
      singulars
      1. PO
      1. USAndrea Ambu
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload