is this what it means that x and y are the same object not just the values that they are basically connected ? or I'm getting the 'is' statement wrong
>>> x=[2,8]
>>> y=x
>>> x.reverse()
>>> y
[8, 2]
>>> y is x
True
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http://nedbatchelder.com/text/names1.html is a great pycon presentation (or just read it; the blog post contains everything in the video) that tells everything everyone absolutely needs to know about names in Python to really understand the language. – Wooble May 27 '16 at 12:18
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@Wooble will do right away ,thanx for recommendation ^^ – Ahmed Elbarky May 27 '16 at 12:26
2 Answers
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You have it exactly right on all counts, they are the same object, and that is what is is meant to show. = does not make a copy. One way to copy the list is with y = list(x).
Alex Hall
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The difference between shallow and deep copy may be a good reading to understand this... in depth: https://docs.python.org/2/library/copy.html – Jacques Gaudin May 27 '16 at 12:22
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That's right, they are exactly the same object - they a sharing the same memory address. If you modify one, you modify them both, like so:
x = [2, 8]
y = x
x.reverse()
print(y) # [8, 2]
If you don't want this you can make a copy using y = x[:].
Pep_8_Guardiola
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