CODEWITHSUNDEEP
python
Chyanit Singh
Chyanit Singh

Reputation: 113

Internal working of an iterator in python

I have one question when we call an iter(obj)on an iterable(list_1). It returns an iterator object. When we invoke the next method on this iterator object it returns the next value one at a time. My question is does the iterator object(iter_obj) contains the data(after we run the iter method) and it prints out the value one at a time or does it reference/use the iterable(list_1) when running the next(method) 

list_1=[1,2,3,4]

iter_obj=iter(list_1)

next(iter_obj)

Upvotes: 1

Views: 287

Answers (1)

mrh1997
mrh1997

Reputation: 1138

Your second assumption (iterator contains reference to list) is true.

If you have a look into the C source code of the iter object you'll see that it contains exactly two attributes:

  • it_index: the index within the sequence ìt_seq of the next object that shall be returned by iter()
  • it_seq: the sequence (in your case list_1) that shall be iterated

Upvotes: 4

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