Reverse function python? How to use?

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  • frankie_85

    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 pointersguideli nes / on how to do it?

    Code:
    a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
    b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
    c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
    d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
    e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
    Thanks in advance

  • Nick Vatamaniuc

    #2
    Re: Reverse function python? How to use?

    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 pointersguideli nes / on how to do it?
    >
    Code:
        a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
        b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
        c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
        d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
        e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
    >
    Thanks in advance

    Comment

    • Murali

      #3
      Re: Reverse function python? How to use?

      Something like this?

      Code:
      foo = [x1,x2,x3,x4,x5]
      bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
      bar.reverse()
      print bar
      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 pointersguideli nes / on how to do it?
      >
      Code:
          a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
          b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
          c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
          d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
          e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
      >
      Thanks in advance

      Comment

      • Ben Finney

        #4
        Re: Reverse function python? How to use?

        "frankie_85 " <steveadi@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

        Comment

        • jmcantrell@gmail.com

          #5
          Re: Reverse function python? How to use?

          If you wanted to keep the original list intact, you could do...

          Code:
          foo = [x1,x2,x3,x4,x5]
          bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
          bar_reversed = reversed(bar)
          On Oct 29, 4:23 pm, "Murali" <gmkrishn.u...@ gmail.comwrote:
          Something like this?
          >
          Code:
          foo = [x1,x2,x3,x4,x5]
          bar = [math.sqrt(math.fabs(x))+5*math.pow(x,3) for x in foo]
          bar.reverse()
          print bar
          >
          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 pointersguideli nes / on how to do it?
          >
          Code:
               a = str(math.sqrt(math.fabs(x1)) + 5*((math.pow(x1,3))))
               b = str(math.sqrt(math.fabs(x2)) + 5*((math.pow(x2,3))))
               c = str(math.sqrt(math.fabs(x3)) + 5*((math.pow(x3,3))))
               d = str(math.sqrt(math.fabs(x4)) + 5*((math.pow(x4,3))))
               e = str(math.sqrt(math.fabs(x5)) + 5*((math.pow(x5,3))))
          >
          Thanks in advance

          Comment

          • Kay Schluehr

            #6
            Re: Reverse function python? How to use?

            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 ?

            Comment

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