John Salerno wrote:
Steve Holden wrote:
Assignment to a list *element* rebinds the single element to the
assigned value.
Ok, I understand that.
Assignment to a list *slice* has to be of a list [or iterable, as per
Duncan], and it
replaces the elements in the slice by assigned elements.
I don't understand the second part of that sentence. I'm assuming "it"
refers to the list being assigned, "replaces the elements" is
self-evident, but what does "by assigned elements" refer to? It seems
when you assign a list to a list slice, nothing gets replaced, the slice
just gets deleted.
Deletion occurs *only* in the corner case where there are no "assigned
elements" i.e. only if the RHS list (sequence) is *empty*. Otherwise
there would be no point at all in the language having assignment to a
slice -- del L[0:2] would suffice.
Study these:
>>> L = [1, 2, 3, 4, 5]
>>> L[0:2] = []
>>> L
[3, 4, 5]
>>> L = [1, 2, 3, 4, 5]
>>> L[0:2] = ['whatever']
>>> L
['whatever', 3, 4, 5]
>>> L = [1, 2, 3, 4, 5]
>>> L[0:2] = tuple('foobar')
>>> L
['f', 'o', 'o', 'b', 'a', 'r', 3, 4, 5]
>>>
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