If I have
a = [[1, 1], [1, 2]]
b = [[1, 1], [1, 2], [1, 3]]
Where a and b are numpy arrays, how can I get this?
c = b - a = [[1, 3]]
Because np.delete does it by index not value. I have tried to create a new array like this
for arr in b:
if arr not in a:
new.append(arr)
But it doesn't work, what am I doing wrong?
A few observations you should know:
numpy has nothing to do with what you showed.remove. This is a o(n) operation.a = [1, 1]
b = [[1, 1], [1, 2]]
print(b)
b.remove(a)
print(b)
out:
[[1, 1], [1, 2]]
[[1, 2]]
Python provides a very powerful list feature "List Comprenhensions" that produce an effective and versatile way to conduct list manipulations in a very adaptable manner.
Considering the input lists you have provided, the output can be dervied within an optimal complexity :
a = [1, 1]
b = [[1, 1], [1, 2]]
c = [x for x in b if x != a]
print(c)
Printing 'c' will provide you :
[[1, 2]]
Note: Using built - in list method of remove() also assists in the same, but I just wanted to emphasize on the value of List Comprehensions in a dynamic language like Python.
