Python 字典，其中值是列表，如何从每个列表值中删除第 X 项

Question

I have dictionary in the form of:

dict_one =  { key2: [val1, val2, val3], key2: [val1, val2, val3] }

I want to remove 'val3' from every element in the dictionary. I believe this should be possible via a for loop but I can't seem to get it correct. I've tried the following:

for lst in dict_one:
    dict_one.pop(dict_one[lst][2])

This is intended, I believe, to remove both key and value. It returned a 'keyerror' error message. dict_one.remove() is clearly not going to work as it's meant for lists. It seems like what I'm trying to do should be relatively simple but I seem to be missing something.

(FYI, it seems like if I only wanted to delete a subset of the 'val3' items, I could follow the approach here: Remove element in dictionary of lists )

Answer 1

First, to remove an item from a list:

l = [val1, val2, val3]
l.remove(val3)

Now looping through lists in dictionary:

dict_once = {key1: [val1, val2, val3], key2: [val1, val2, va3]}
for inner_list in dict_one.values():
    inner_list.remove(val3)

Or, looping through using keys:

for key in dict_one:
    dict_one[key].remove(val3)

Answer 2

To get a specific item from list of dictionary:

for lst in dict_one:
    print(dict_one.get(lst)[item_num])

to modify an entry:

for lst in dict_one:
    dict_one[lst] = new_value
    print(dict_one.get(lst))

The changes you wanted to your lists:

dict_one =  { 'key2': ['val1', 'val2', 'val3'], 'key3': ['val1', 'val2', 'val3'] }

for lst in dict_one:
    dict_one[lst] = dict_one.get(lst)[:-1]
    print(dict_one.get(lst))

Answer 3

One way using dict comprehension:

dict_one = {'key2': ['val1', 'val2', 'val3'], 'key3': ['val1', 'val2', 'val3']}
dict_two = {k: v[:-1] for k, v in dict_one.items()}
print(dict_two)

Output:

{'key2': ['val1', 'val2'], 'key3': ['val1', 'val2']}

Answer 4

dict_one = {"key2": ["val1", "val2", "val3"], "key3": ["val1", "val2", "val3"]}
for lst in dict_one:
    dict_one[lst] = dict_one.get(lst)[:-1]
print dict_one