numpy or _numpy or Numeric?

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  • auditory
    #1

    numpy or _numpy or Numeric?

    I am a newbie here

    I am trying to read "space separated floating point data" from file

    I read about csv module by searching this group,
    but I couldn't read space separated values with csv.
    (which may be matter of course..)

    I also read about numpy.fromfile( file, sep=' ') which i can use.
    but on my machine(ubuntu linux) numpy is unknown module,
    which I didn't install by myself.

    While trying to install numpy accroding to its homepage.
    (http://numpy.scipy.org/numpydoc/numdoc.htm).
    i am quite confused.

    it's talking about the Numerical Python,
    and it says to test whether it is installed or not,
    try import Numeric instead of numpy.

    I got Nurmeric modules and
    as a matter of fact i got a file named '_numpy.so' in lib directory.

    I can import _numpy but _numpy does not have 'fromfile' method

    My question is:
    1. Do i need to install numpy module?
    2. Then Is it different from Numeric module?
    3. Then where can i get it?

    4. Or what is general way to read 'space separated values' from file?

    Thanks in advance.
    Tags: None
    • Travis E. Oliphant
      #2
      Re: numpy or _numpy or Numeric?

      auditory wrote:
      I am a newbie here
      >
      I am trying to read "space separated floating point data" from file
      >
      I read about csv module by searching this group,
      but I couldn't read space separated values with csv.
      (which may be matter of course..)
      >
      I also read about numpy.fromfile( file, sep=' ') which i can use.
      but on my machine(ubuntu linux) numpy is unknown module,
      which I didn't install by myself.
      You will need to install NumPy.
      >
      While trying to install numpy accroding to its homepage.
      (http://numpy.scipy.org/numpydoc/numdoc.htm).
      i am quite confused.
      You are reading old documentation for Numeric and so any installation
      description is how to install the Numeric module (not its newer
      replacement which is called NumPy).


      So:

      1) Yes, you need NumPy
      2) This *is different* from Numeric
      3) You get it by either installing a pre-built package for your system
      or by

      a) downloading the source tar-file from
      http://sourceforge.net/project/showf...kage_id=175103
      (get the numpy-<version>.tar.g z file
      b) tar zxvf numpy-<version>.tar.g z
      c) cd numpy-<version>
      d) sudo python setup.py install

      e) If you want to link against high-performance libraries on your
      system, then either put them in standard locations or edit the site.cfg
      file appropriately (Optional).
      >
      4. Or what is general way to read 'space separated values' from file?
      You can easily read space-separated values from a file by reading in a
      line at a time and using the split method of strings:

      fid = open('filename' )
      linedata = fid.readlines()
      new = [[float(x) for x in line.split()] for line in linedata]

      new will be a nested sequence of floats. You can convert it to an array
      (if you want to do math on it) using

      anew = numpy.array(new )

      -Travis

        Comment

        • George Sakkis
          #3
          Re: numpy or _numpy or Numeric?

          On Jan 24, 2:24 am, auditory <pkyo...@gmail. comwrote:
          I am a newbie here
          >
          I am trying to read "space separated floating point data" from file
          >
          I read about csv module by searching this group,
          but I couldn't read space separated values with csv.
          (which may be matter of course..)
          >
          I also read about numpy.fromfile( file, sep=' ') which i can use.
          but on my machine(ubuntu linux) numpy is unknown module,
          which I didn't install by myself.
          >
          While trying to install numpy accroding to its homepage.
          (http://numpy.scipy.org/numpydoc/numdoc.htm).
          i am quite confused.
          >
          it's talking about the Numerical Python,
          and it says to test whether it is installed or not,
          try import Numeric instead of numpy.
          >
          I got Nurmeric modules and
          as a matter of fact i got a file named '_numpy.so' in lib directory.
          >
          I can import _numpy but _numpy does not have 'fromfile' method
          >
          My question is:
          1. Do i need to install numpy module?
          2. Then Is it different from Numeric module?
          3. Then where can i get it?
          >
          4. Or what is general way to read 'space separated values' from file?
          >
          Thanks in advance.
          If *all* you need is to read a space-separated file with floating point
          values, installing numpy (or Numeric or numarray..) is an overkill; you
          can do it in one line in pure Python:

          matrix = [map(float, line.split()) for line in
          open('my_space_ separated_file. txt')]

          This stores the values as a list of lists, each list corresponding to a
          row in the file. Depending on what you plan to do next with these
          numbers, this may or may not be the best way to go about it, but since
          you only mentioned the file reading part, we can't assume much.

          George

            Comment

            • auditory
              #4
              Re: numpy or _numpy or Numeric?

              George Sakkis ? ?:
              On Jan 24, 2:24 am, auditory <pkyo...@gmail. comwrote:
              >
              >I am a newbie here
              >>
              >I am trying to read "space separated floating point data" from file
              >>
              >I read about csv module by searching this group,
              >but I couldn't read space separated values with csv.
              >(which may be matter of course..)
              >>
              >I also read about numpy.fromfile( file, sep=' ') which i can use.
              >but on my machine(ubuntu linux) numpy is unknown module,
              >which I didn't install by myself.
              >>
              >While trying to install numpy accroding to its homepage.
              >(http://numpy.scipy.org/numpydoc/numdoc.htm).
              >i am quite confused.
              >>
              >it's talking about the Numerical Python,
              >and it says to test whether it is installed or not,
              >try import Numeric instead of numpy.
              >>
              >I got Nurmeric modules and
              >as a matter of fact i got a file named '_numpy.so' in lib directory.
              >>
              >I can import _numpy but _numpy does not have 'fromfile' method
              >>
              >My question is:
              >1. Do i need to install numpy module?
              >2. Then Is it different from Numeric module?
              >3. Then where can i get it?
              >>
              >4. Or what is general way to read 'space separated values' from file?
              >>
              >Thanks in advance.
              >
              If *all* you need is to read a space-separated file with floating point
              values, installing numpy (or Numeric or numarray..) is an overkill; you
              can do it in one line in pure Python:
              >
              matrix = [map(float, line.split()) for line in
              open('my_space_ separated_file. txt')]
              >
              This stores the values as a list of lists, each list corresponding to a
              row in the file. Depending on what you plan to do next with these
              numbers, this may or may not be the best way to go about it, but since
              you only mentioned the file reading part, we can't assume much.
              >
              George
              >
              Thanks a lot for your 'elegant' suggestion.
              As a next step i wish to do some math with matrix and produce a vector
              and write it on a file. (in fact math is just averaging now)

              I hope i can do this with a little more efforts.

                Comment

                • auditory
                  #5
                  Re: numpy or _numpy or Numeric?

                  Travis E. Oliphant ? ?:
                  auditory wrote:
                  >I am a newbie here
                  >>
                  >I am trying to read "space separated floating point data" from file
                  >>
                  >I read about csv module by searching this group,
                  >but I couldn't read space separated values with csv.
                  >(which may be matter of course..)
                  >>
                  >I also read about numpy.fromfile( file, sep=' ') which i can use.
                  >but on my machine(ubuntu linux) numpy is unknown module,
                  >which I didn't install by myself.
                  >
                  You will need to install NumPy.
                  >
                  >>
                  >While trying to install numpy accroding to its homepage.
                  >(http://numpy.scipy.org/numpydoc/numdoc.htm).
                  >i am quite confused.
                  >
                  You are reading old documentation for Numeric and so any installation
                  description is how to install the Numeric module (not its newer
                  replacement which is called NumPy).
                  >
                  >
                  So:
                  >
                  1) Yes, you need NumPy
                  2) This *is different* from Numeric
                  3) You get it by either installing a pre-built package for your system
                  or by
                  >
                  a) downloading the source tar-file from
                  http://sourceforge.net/project/showf...kage_id=175103
                  >
                  (get the numpy-<version>.tar.g z file
                  b) tar zxvf numpy-<version>.tar.g z
                  c) cd numpy-<version>
                  d) sudo python setup.py install
                  >
                  e) If you want to link against high-performance libraries on your
                  system, then either put them in standard locations or edit the site.cfg
                  file appropriately (Optional).
                  >
                  >>
                  >4. Or what is general way to read 'space separated values' from file?
                  >
                  You can easily read space-separated values from a file by reading in a
                  line at a time and using the split method of strings:
                  >
                  fid = open('filename' )
                  linedata = fid.readlines()
                  new = [[float(x) for x in line.split()] for line in linedata]
                  >
                  new will be a nested sequence of floats. You can convert it to an array
                  (if you want to do math on it) using
                  >
                  anew = numpy.array(new )
                  >
                  -Travis
                  >
                  Thank you for quick answer..

                  I found the above website from googling with "numpy" keyword,
                  and supprised at that the top matching page is old one.

                  In addition to your method and below one,
                  I found csv moudule can do this with "delimiter" paramter.
                  I made mistake not to read manual first.
                  My apology on that.

                    Comment

                    • Travis E. Oliphant
                      #6
                      Re: numpy or _numpy or Numeric?

                      auditory wrote:
                      >>While trying to install numpy accroding to its homepage.
                      >>(http://numpy.scipy.org/numpydoc/numdoc.htm).
                      >>i am quite confused.
                      >You are reading old documentation for Numeric and so any installation
                      >description is how to install the Numeric module (not its newer
                      >replacement which is called NumPy).
                      >
                      I found the above website from googling with "numpy" keyword,
                      and supprised at that the top matching page is old one.
                      >
                      The website is not the old one. http://numpy.scipy.org is correct.

                      But, the documentation is old. But, it is still useful (except for
                      Numeric specific information like how to install it). Therefore we
                      still make a link to it.

                      -Travis

                        Comment

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