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Created on 2012-12-23 16:33 by jenda.petrov@gmail.com, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Messages (2) | |||
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| msg177995 - (view) | Author: jp (jenda.petrov@gmail.com) | Date: 2012-12-23 16:33 | |
The following code:
li = [[1,0]]*5
a = [[1,10], [2,20], [3,30]]
for line in a:
li[line[0]][0] = 2
print(li)
prints [[2,0],[2,0],[2,0],[2,0],[2,0]], but should print [[1,0],[2,0],[2,0],[2,0],[1,0]].
The output is correct if you, instead of using li = [[1,0]]*5, initialize the array as follows:
li = []
for i in range(5): li.append([1,0])
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| msg177996 - (view) | Author: Christian Heimes (christian.heimes) *  |
Date: 2012-12-23 16:40 | |
The outcome is correct. You have fallen for a common beginners gotcha: http://www.enricozini.org/2011/tips/python-list-gotcha |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:39 | admin | set | github: 60960 |
| 2012-12-23 16:40:18 | christian.heimes | set | status: open -> closed nosy: + christian.heimes messages: + msg177996 resolution: not a bug |
| 2012-12-23 16:33:03 | jenda.petrov@gmail.com | create | |