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Python Forum > Python Coding > General Coding Help > why does the list of list replicate this way?
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hshivaraj

Nov-30-2017, 05:36 PM


a = [[]] * 10

a
[[], [], [], [], [], [], [], [], [], []]

a[0].append((1,2))

a
[[(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)], [(1, 2)]]
Why does it replicate the values across the entire list? Bizarre Huh

Windspar

Nov-30-2017, 06:28 PM
Because list are reference. [[]] * 10 makes 10 reference copies.
a = [[] for x in range(10)]

hshivaraj

Dec-01-2017, 10:53 AM
Thanks very much windspar.
That was as simple as that :)
Python Forum > Python Coding > General Coding Help > why does the list of list replicate this way?