copying generatrors

[Horace Enea]

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

[Matimus]

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

[Horace Enea]

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 <11**********************@o11g2000prd.googlegroups .com>,
Matimus <mc******@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

[Steven Bethard]

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

[Horace Enea]

Steve,

Hey, thanks. I'll try that.

Horace

In article <-J******************************@comcast.com>,
Steven Bethard <st************@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