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Reverse function python? How to use?

Ok I'm really lost (I'm new to python) how to use the reverse function.
I made a little program which basically the a, b, c, d, e which I have
listed below and basically I want it th result to be printed reverse so
instead doing "print e, d, c, b, a", I'd like to use the reverse
function

Can someone give pointersguidelines / on how to do it?

Expand|Select|Wrap|Line Numbers
  1. a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
  2. b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
  3. c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
  4. d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
  5. e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
  6.  
Thanks in advance

Oct 29 '06 #1
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5 Replies
Use the list's reverse() function. The only thing to keep in mind is
that it will reverse in-place.
Here is an example:
--------------------------------
In [1]: l=[1,2,3]

In [2]: l.reverse()

In [3]: l
Out[3]: [3, 2, 1]
------------------------------------
So you could accumulate your results in a list then apply reverse() on
it.

Hope this helps,
Nick Vatamaniuc
frankie_85 wrote:
Ok I'm really lost (I'm new to python) how to use the reverse function.
I made a little program which basically the a, b, c, d, e which I have
listed below and basically I want it th result to be printed reverse so
instead doing "print e, d, c, b, a", I'd like to use the reverse
function

Can someone give pointersguidelines / on how to do it?

Expand|Select|Wrap|Line Numbers
  1.     a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
  2.     b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
  3.     c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
  4.     d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
  5.     e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
  6.  

Thanks in advance
Oct 29 '06 #2
Something like this?

Expand|Select|Wrap|Line Numbers
  1. foo = [x1,x2,x3,x4,x5]
  2. bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
  3. bar.reverse()
  4. print bar
  5.  
frankie_85 wrote:
Ok I'm really lost (I'm new to python) how to use the reverse function.
I made a little program which basically the a, b, c, d, e which I have
listed below and basically I want it th result to be printed reverse so
instead doing "print e, d, c, b, a", I'd like to use the reverse
function

Can someone give pointersguidelines / on how to do it?

Expand|Select|Wrap|Line Numbers
  1.     a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
  2.     b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
  3.     c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
  4.     d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
  5.     e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
  6.  

Thanks in advance
Oct 29 '06 #3
"frankie_85" <st******@gmail.comwrites:
I made a little program which basically the a, b, c, d, e which I
have listed below and basically I want it th result to be printed
reverse so instead doing "print e, d, c, b, a", I'd like to use the
reverse function
As was pointed out before, your assignment requires you to use a
list. You're using completely distinct names instead of storing these
sequences in a container. Read your course notes again, paying
attention to "containers" and especially "lists".

--
\ "For of those to whom much is given, much is required." -- |
`\ John F. Kennedy |
_o__) |
Ben Finney

Oct 29 '06 #4
If you wanted to keep the original list intact, you could do...

Expand|Select|Wrap|Line Numbers
  1. foo = [x1,x2,x3,x4,x5]
  2. bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
  3. bar_reversed = reversed(bar)
  4.  
On Oct 29, 4:23 pm, "Murali" <gmkrishn.u...@gmail.comwrote:
Something like this?

Expand|Select|Wrap|Line Numbers
  1. foo = [x1,x2,x3,x4,x5]
  2. bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
  3. bar.reverse()
  4. print bar
  5.  

frankie_85 wrote:
Ok I'm really lost (I'm new to python) how to use the reverse function.
I made a little program which basically the a, b, c, d, e which I have
listed below and basically I want it th result to be printed reverse so
instead doing "print e, d, c, b, a", I'd like to use the reverse
function
Can someone give pointersguidelines / on how to do it?
Expand|Select|Wrap|Line Numbers
  1.      a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
  2.      b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
  3.      c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
  4.      d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
  5.      e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
  6.  
Thanks in advance
Oct 30 '06 #5
frankie_85 wrote:
Ok I'm really lost (I'm new to python) how to use the reverse function.
I made a little program which basically the a, b, c, d, e which I have
listed below and basically I want it th result to be printed reverse so
instead doing "print e, d, c, b, a", I'd like to use the reverse
function
You can use extended slice operators

http://www.python.org/doc/2.3.5/what...on-slices.html [1]

This function call should do what yo expect

print [e, d, c, b, a][::-1]

[1] Does anyone know where to find a comprehensible description of
enhanced slices in the Python docs besides an an aged "What's new?"
column? Or is it intended that newbies read this
http://docs.python.org/ref/slicings.html ?

Oct 30 '06 #6

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