I have a list containing my data, in the following form:
data = [[[1, 3, 4, 5, 7], [A, B, C]],
[[2, 3, 8, 2, 9], [F, C, C]],
[[6, 3, 1, 3, 1], [F, E, D]],
[[2, 3, 7, 0, 3], [F, C, F]],
[[0, 3, 3, 4, 5], [F, B, A]]]
In my program, I would check if there is a column that has a fixed value (like the second column that contains only 3s. If found, I should remove it from the data. One of the solutions that we could iterate over the list and remove this column element by element. with the following code:
for data_line in data:
del data_line 
Is this OK or not? Can this cause instability or any other problem?
Thanks in advance
Summary of solutions
Thanks for all who contributed to this question
, to summarize the valuable contributions below we can say:
It is OK to modify the contents of the list you are iterating over it, but not to remove elements of it, i.e. wherever the modification does not change the length of the MAIN list, then no problem.