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+--- Thread: Why does this list of lists end up with the same values (/thread-19882.html)
Why does this list of lists end up with the same values - alehak - Jul-18-2019
How can this be explained?
x = [[]]*3
x[0].append('a')
print(x)>>> returns [['a'], ['a'], ['a']]
RE: Append working - stranac - Jul-18-2019
After you execute
x = [[]]*3, x is a list containing 3 references to the same list. Basically, you've given the inner list three names: x[0], x[1] and x[2].When you modify the list, you can see the change no matter which name you use.
The same would happen if you did this:
>>> a = b = [] >>> a.append(1) >>> b [1]You probably wanted to create 3 distinct lists, e.g.:
x = [[] for _ in range(3)]
RE: Why does this list of lists end up with the same values - perfringo - Jul-18-2019
You can read or watch Ned Batchelder's Python Names and Values. This should answer you question in pretty comprehensive way.