sgt_20220926_dict_exer3.py

# # 3. Dictionary cleaner

# 3a. Write clean_dict_value(d, bad_val), which returns a cleaned dictionary without any keys with
# the value bad_val

# The parameters of the function are the dictionary d to be processed and the value bad_val
# to be disposed of together with its key.

# Example:

# clean_dict_value ({'a': 5, 'b': 6, 'c': 5}, 5) -> {'b': 6}, because 5 was a value for both a and c keys to get rid of.

# 3b Write clean_dict_values ​​(d, v_list), which returns a cleaned dictionary

# The parameters of the function are the dictionary d to be processed and the list of values
# v_list to get rid of.

# clean_dict_values ​​({'a': 5, 'b': 6, 'c': 5, 'd':3}, [3,4,5]) -> {'b': 6}
# because 3 and 5 were in the list of values to delete.


# PS. Remember we can use del d['a'] only if the key 'a' exists.

# !! When resizing a dictionary, we are not allowed to iterate at the same time!

# There are two options: either walk through the copy my_dict.copy.items(), or build a new dictionary. 
# Dictionary comprehension would be one option.

def replace_dict_value(d, bad_val, good_val):
    new_dict = {}
    for key, value in d.items():
        if value != bad_val:
            new_dict[key] = value
        if value == bad_val:
            new_dict[key] = good_val
    return new_dict

print(replace_dict_value({'a': 5, 'b': 6, 'c': 5}, 5, 30)) 

my_dict = {'a': 5, 'b': 6, 'c': 5, 'd':3, 'e': 5, 'f': 5, 'g':8}	
new_dict = replace_dict_value(my_dict, 8)
print(new_dict)
print(my_dict)