Your question involves a mix of basic Python syntax, and numpy specific details. In many ways it is the same for lists, but not exactly. arr[:, 0] returns the 1st column of arr (a view), arr[:,0]=10 sets the values of that column to 10. arr[:] returns arr (alist[:] returns a copy of a list). arr[:]=arr2 performs an inplace replacement; changing the values of arr to the values of arr2. The ...
The first element was not selected, which was expected. And if I change 0 to -1, i.e, if I try: arr[len(arr)-1: -1: -1] OR even arr[:-1:-1], I get an empty array. Apparently I get the reversed array view by: arr[::-1] Q: How is this working? If I do not specify the first two arguments how does it infer that it needs to continue till 0? In fact it is just interpreting that it needs to go till ...
As others have mentioned, *(&arr + 1) triggers undefined behavior because &arr + 1 is a pointer to one-past-the end of an array of type int [7] and that pointer is subsequently dereferenced.
How *(&arr + 1) - arr is working to give the array size
Suppose I have an array of integers called arr. I am trying to understand the distinction between *&arr and *&arr [0]. I read that in C++, arr is essentially a pointer to the first element...