copying generatrors

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  • Horace Enea
    #1

    copying generatrors

    Does anyone have code to copy a generator?

    Here is what I'd like to do:

    def foo():
    yield 1
    yield 2
    yield 3

    f = foo()
    g = copy(foo)

    print f.next()
    1
    print f.next()
    2

    print g.next()
    1

    Thanks,

    Horace
    Tags: None
    • Matimus
      #2
      Re: copying generatrors

      Why not just do this:
      >>def foo():
      .... yield 1
      .... yield 2
      .... yield 3
      ....
      >>f = foo()
      >>g = foo()
      >>f.next()
      1
      >>f.next()
      2
      >>f.next()
      3
      >>g.next()
      1
      >>g.next()
      2
      >>g.next()
      3

        Comment

        • Horace Enea
          #3
          Re: copying generatrors

          My example wasn't very good. Here's another try:

          def foo():
          yield 1
          yield 2
          yield 3

          f = foo()
          f.next()
          1

          g=copy(f) # copy the generator after an iteration

          f.next()
          2
          f.next()
          3

          g.next()
          2

          I want to copy the generator's state after one or more iterations.





          In article <1181087423.361 999.324710@o11g 2000prd.googleg roups.com>,
          Matimus <mccredie@gmail .comwrote:
          Why not just do this:
          >
          >def foo():
          ... yield 1
          ... yield 2
          ... yield 3
          ...
          >f = foo()
          >g = foo()
          >f.next()
          1
          >f.next()
          2
          >f.next()
          3
          >g.next()
          1
          >g.next()
          2
          >g.next()
          3

            Comment

            • Steven Bethard
              #4
              Re: copying generatrors

              Horace Enea wrote:
              My example wasn't very good. Here's another try:
              >
              def foo():
              yield 1
              yield 2
              yield 3
              >
              f = foo()
              f.next()
              1
              >
              g=copy(f) # copy the generator after an iteration
              >
              f.next()
              2
              f.next()
              3
              >
              g.next()
              2
              >
              I want to copy the generator's state after one or more iterations.
              You could use itertools.tee() :
              >>def foo():
              .... yield 1
              .... yield 2
              .... yield 3
              ....
              >>import itertools
              >>f = foo()
              >>f.next()
              1
              >>f, g = itertools.tee(f )
              >>f.next()
              2
              >>f.next()
              3
              >>g.next()
              2
              >>g.next()
              3

              But note that if your iterators get really out of sync, you could have a
              lot of elements stored in memory.

              STeVe

                Comment

                • Horace Enea
                  #5
                  Re: copying generatrors

                  Steve,

                  Hey, thanks. I'll try that.

                  Horace

                  In article <-JKdnb0ntvytmvvb nZ2dnUVZ_o_inZ2 d@comcast.com>,
                  Steven Bethard <steven.bethard @gmail.comwrote :
                  Horace Enea wrote:
                  My example wasn't very good. Here's another try:

                  def foo():
                  yield 1
                  yield 2
                  yield 3

                  f = foo()
                  f.next()
                  1

                  g=copy(f) # copy the generator after an iteration

                  f.next()
                  2
                  f.next()
                  3

                  g.next()
                  2

                  I want to copy the generator's state after one or more iterations.
                  >
                  You could use itertools.tee() :
                  >
                  >>def foo():
                  ... yield 1
                  ... yield 2
                  ... yield 3
                  ...
                  >>import itertools
                  >>f = foo()
                  >>f.next()
                  1
                  >>f, g = itertools.tee(f )
                  >>f.next()
                  2
                  >>f.next()
                  3
                  >>g.next()
                  2
                  >>g.next()
                  3
                  >
                  But note that if your iterators get really out of sync, you could have a
                  lot of elements stored in memory.
                  >
                  STeVe

                    Comment

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