Re:W3schools.dev Redirects to Mozilla Developer Network
by jerf on Friday March 01, 2019 @10:33AM
(#19281510)
As always, as you say, it depends on your definition.
One of the useful definitions of an array is that it guarantees contiguous storage in memory. In Python, there is no way to guarantee that; even if a list is a C array of Python references under the hood, there's no way to store the information represented by those references contiguously in memory. From that perspective, pure Python doesn't have any arrays at all, which is precisely why the popular NumPy has to offer explicit support for numeric arrays.
From another perspective, arrays are a set of O() guarantees for various operations. From that perspective, Python lists will generally meet the specifications that you'd write for a resizable array, or perhaps what you might call "vector", depending. CPython comes with some awful constant factors but the O() of the lists will be what you'd expect.
Rather than arguing about whether Python has "arrays" interminably, it's better to carefully define array, then dispassionately examine Python lists to see if they match that definiton. You'll get a yes sometimes and no others. I say "dispassionately" because too many people seem to assign moral qualities to whether or not something conforms to a given definition, but that's not a path to understanding. No matter what definition you write down for "array", not a single characteristic of Python will change.
One of the useful definitions of an array is that it guarantees contiguous storage in memory. In Python, there is no way to guarantee that; even if a list is a C array of Python references under the hood, there's no way to store the information represented by those references contiguously in memory. From that perspective, pure Python doesn't have any arrays at all, which is precisely why the popular NumPy has to offer explicit support for numeric arrays.
From another perspective, arrays are a set of O() guarantees for various operations. From that perspective, Python lists will generally meet the specifications that you'd write for a resizable array, or perhaps what you might call "vector", depending. CPython comes with some awful constant factors but the O() of the lists will be what you'd expect.
Rather than arguing about whether Python has "arrays" interminably, it's better to carefully define array, then dispassionately examine Python lists to see if they match that definiton. You'll get a yes sometimes and no others. I say "dispassionately" because too many people seem to assign moral qualities to whether or not something conforms to a given definition, but that's not a path to understanding. No matter what definition you write down for "array", not a single characteristic of Python will change.