[Tutor] Python Generator expressions

[Mats Wichmann]

On 7/23/19 11:06 AM, Animesh Bhadra wrote:
> Hi All,
> 
> Need one help in understanding generator expression/comprehensions.
> 
> This is my sample code.
> 
> # This code creates a generator and not a tuple comprehensions.
> my_square =(num *num fornum inrange(11))
> print(my_square) # <generator object <genexpr> at 0x7f3c838c0ca8>
> # We can iterate over the square generator like this.
> try:
> whileTrue:
> print(next(my_square)) # Prints the value 0,1,4....
> exceptStopIterationasSI:
> print("Stop Iteration")

is this code you were actually running? because it won't work... an
except needs to be matched with a try, it can't match with a while.

you *can* comsume your the values your generator expression generates by
doing a bunch of next's, but why would you?  Instead, just iterate over
it (every generator is also an iterator, although not vice versa):

for s in my_square:
    print(s)

you don't have to manually catch the StopIteration here, because that's
just handled for you by the loop.


> # Another iteration
> forx inmy_square:
> print(x) # This prints nothing.
> 
> 
> Does the generator exhausts its values when we run the iterator once?
> Lastly any specific reason for not having a tuple comprehensions?
> 
> Have checked this link, but could not understood the reason?
> 
>  *
> https://stackoverflow.com/questions/16940293/why-is-there-no-tuple-comprehension-in-python
> 
> 
> Regards,
> Animesh
> 
> 
> 
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> https://mail.python.org/mailman/listinfo/tutor