Does Python do slice-by-reference on strings?

Solution 1:

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.

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.

Apparently, if you absolutely need a view into a string, you can use a memoryview object.