How to compare values of actual key and the previous one?-CodePudding

I have a dictionary and inside of the values are lists which contain 2 numbers.

For example:

z_n = {'1': [[4, 7], [7, 8], [7, 9], [6, 7]], '2': [[4, 5], [8, 10], [3, 4]]}

First I want to remove the number 7 of all lists inside of the value from the first key.

That works like this:

root = 7

# Iterating through dictionary z_n
for key, value in z_n.items():

    # Iterating through lists of values
    for lis in value:

        #
        if root in lis:

            # Removing 7 from the list
            lis.remove(root)

For the first key it will be like this:

z_n = {'1': [[4], [8], [9], [6]], '2': [[4, 5], [8, 10], [3, 4]]}

From the following keys now on I want to compare their values with the values from the previous key and remove them again from each list.

In this case I want to remove 4, 8, 9 and 6 if they are in '2': [[4, 5], [8, 10], [3, 4]] so that it will be like this:
'2': [[5],[10],[3]].

How is it possible to compare each value of the actual key to all values from the previous key and remove them if they are inside both?

CodePudding user response：

This is my solution:

import itertools

def remove_func(sublist, remove_list):
    new_sublist = []
    for i in sublist:
        temp = []
        for j in i:
            if j not in remove_list:
                temp.append(j)
        new_sublist.append(temp)
        
    return new_sublist
    

z_n = {'1': [[4, 7], [7, 8], [7, 9], [6, 7]], '2': [[4, 5], [8, 10], [3, 4]]}

remove_list = [7]
for key, value in z_n.items():
    z_n[key] = remove_func(z_n[key], remove_list )
    remove_list = list(itertools.chain(*z_n[key]))
    
print(z_n)

Output:

{'1': [[4], [8], [9], [6]], '2': [[5], [10], [3]]}

CodePudding user response：

Picking up from exactly where you are stuck, i.e. I'm assuming you have removed number 7 from your first key in the dictionary.

You can first create a set for all the values for first key, then filter out the values in list of list of values in second key:

values=set(x for v in z_n['1'] for x in v)
z_n['2'] = [[v for v in x if v not in values] for x in z_n['2']]

# z_n
{'1': [[4], [8], [9], [6]], '2': [[5], [10], [3]]}

CodePudding user response：

Here's another approach using sets:

z_n = {'1': [[4, 7], [7, 8], [7, 9], [6, 7]], '2': [[4, 5], [8, 10], [3, 4]]}

root = 7

s = {root}

for i, k in enumerate(z_n.keys()):
    z_n[k] = [list(set(e) - s) for e in z_n[k]]
    if i == 0:
        s = {e[0] for e in z_n[k]}

print(z_n)

Output:

{'1': [[4], [8], [9], [6]], '2': [[5], [10], [3]]}