How can I compare two ordered lists in python?
Question:
If I have one long list: myList = [0,2,1,0,2,1] that I split into two lists:
a = [0,2,1]
b = [0,2,1]
how can I compare these two lists to see if they are both equal/identical, with the constraint that they have to be in the same order?
I have seen questions asking to compare two lists by sorting them, but in my specific case, I am not checking for a sorted comparison, but identical list comparison.
Answers:
Just use the classic == operator:
>>> [0,1,2] == [0,1,2]
True
>>> [0,1,2] == [0,2,1]
False
>>> [0,1] == [0,1,2]
False
Lists are equal if elements at the same index are equal. Ordering is taken into account then.
If you want to just check if they are identical or not, a == b should give you true / false with ordering taken into account.
In case you want to compare elements, you can use numpy for comparison
c = (numpy.array(a) == numpy.array(b))
Here, c will contain an array with 3 elements all of which are true (for your example). In the event elements of a and b don’t match, then the corresponding elements in c will be false.
The expression a == b should do the job.
If I have one long list: myList = [0,2,1,0,2,1] that I split into two lists:
a = [0,2,1]
b = [0,2,1]
how can I compare these two lists to see if they are both equal/identical, with the constraint that they have to be in the same order?
I have seen questions asking to compare two lists by sorting them, but in my specific case, I am not checking for a sorted comparison, but identical list comparison.
Just use the classic == operator:
>>> [0,1,2] == [0,1,2]
True
>>> [0,1,2] == [0,2,1]
False
>>> [0,1] == [0,1,2]
False
Lists are equal if elements at the same index are equal. Ordering is taken into account then.
If you want to just check if they are identical or not, a == b should give you true / false with ordering taken into account.
In case you want to compare elements, you can use numpy for comparison
c = (numpy.array(a) == numpy.array(b))
Here, c will contain an array with 3 elements all of which are true (for your example). In the event elements of a and b don’t match, then the corresponding elements in c will be false.
The expression a == b should do the job.