Python: problem with list append

Question

Here is my code -

cumulative_nodes_found_list = []
cumulative_nodes_found_total_list = []

no_of_runs = 10

count = 0

while count < no_of_runs:

 #My program code

 print 'cumulative_nodes_found_list - ' + str(cumulative_nodes_found_list)
 cumulative_nodes_found_total_list.insert(count,cumulative_nodes_found_list)
 print 'cumulative_nodes_found_total_list - ' + str(cumulative_nodes_found_total_list)
 count = count + 1

Here is a part of the output -

#count = 0
cumulative_nodes_found_list - [0.0, 0.4693999, 0.6482, 0.6927999999, 0.7208999999, 0.7561999999, 0.783399999, 0.813999999, 0.8300999999, 0.8498, 0.8621999999]

cumulative_nodes_found_total_list - [[0.0, 0.4693999, 0.6482, 0.6927999999, 0.7208999999, 0.7561999999, 0.783399999, 0.813999999, 0.8300999999, 0.8498, 0.8621999999]]

#count = 1
cumulative_nodes_found_list - [0.0, 0.55979999999999996, 0.66220000000000001, 0.69479999999999997, 0.72040000000000004, 0.75380000000000003, 0.77629999999999999, 0.79679999999999995, 0.82979999999999998, 0.84850000000000003, 0.85760000000000003]

cumulative_nodes_found_total_list -[[0.0, 0.55979999999999996, 0.66220000000000001, 0.69479999999999997, 0.72040000000000004, 0.75380000000000003, 0.77629999999999999, 0.79679999999999995, 0.82979999999999998, 0.84850000000000003, 0.85760000000000003], 
[0.0, 0.55979999999999996, 0.66220000000000001, 0.69479999999999997, 0.72040000000000004, 0.75380000000000003, 0.77629999999999999, 0.79679999999999995, 0.82979999999999998, 0.84850000000000003, 0.85760000000000003]]

As the new item is appended the old item is replaced by new item. This trend continues. Can anyone tell me why this is happening. I have tried using 'append' in place of insert but got the same output. However when I use 'extend' I get the correct output but I need inner items as lists which I dont get with extend.

Answer 1

You need to rebind cumulative_nodes_found_list at the beginning of the loop, instead of just clearing it.