python - deleting entries in a dictionary based on a condition

Question

I have a dictionary with names as key and (age, Date of Birth) tuple as the value for those keys. E.g.

dict = {'Adam' : (10, '2002-08-13'),
        'Eve'  : (40, '1972-08-13')}

I want to delete all the keys which have age > 30 for their age in value tuple, how can I do that? I am accessing age of each key using dict[name][0] where dict is my dictionary.

Answer 1

The usual way is to create a new dictionary containing only the items you want to keep:

new_data = {k: v for k, v in data.items() if v[0] <= 30}

If you need to change the original dictionary in place, you can use a for-loop:

for k, v in list(data.items()):
    if v[0] > 30:
        del data[k]

Note that list(data.items()) creates a shallow copy of the items of the dictionary, i.e. a new list containing references to all keys and values, so it's safe to modify the original dict inside the loop.