I want to know if when I do something like
a = "This could be a very large string..." b = a[:10]
a new string is created or a view/iterator is returned
Python does slice-by-copy, meaning every time you slice (except for very trivial slices, such as a[:]), it copies all of the data into a new string object.
a[:]
According to one of the developers, this choice was made because
The [slice-by-reference] approach is more complicated, harder to implement and may lead to unexpected behavior. For example: a = "a long string with 500,000 chars ..." b = a[0] del a With the slice-as-copy design the string a is immediately freed. The slice-as-reference design would keep the 500kB string in memory although you are only interested in the first character.
The [slice-by-reference] approach is more complicated, harder to implement and may lead to unexpected behavior.
For example:
a = "a long string with 500,000 chars ..." b = a[0] del a
With the slice-as-copy design the string a is immediately freed. The slice-as-reference design would keep the 500kB string in memory although you are only interested in the first character.
a
Apparently, if you absolutely need a view into a string, you can use a memoryview object.
memoryview
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