How to separate a Python list into two lists, according to some aspect of the elements

Question

I have a list like this:

[[8, \"Plot\", \"Sunday\"], [1, \"unPlot\", \"Monday\"], [12, \"Plot\", \"Monday\"], [10, \"Plot\", \"Tuesday\"], [4, \"unPlot\", \"         


        

Answer 1

You could use list comprehensions, e.g.

# old_list elements should be tuples if they're fixed-size, BTW
list1 = [(X, Y, Z) for X, Y, Z in old_list if Y == 'Plot']
list2 = [(X, Y, Z) for X, Y, Z in old_list if Y == 'unPlot']

If you want to traverse the input list only once, then maybe:

def split_list(old_list):
    list1 = []
    list2 = []
    for X, Y, Z in old_list:
        if Y == 'Plot':
            list1.append((X, Y, Z))
        else:
            list2.append((X, Y, Z))
    return list1, list2