5 simple programming problems involving Python dictionaries

1. **Dictionary Initialization:**

Write a program that initializes an empty dictionary called `my_dict` and adds three key-value pairs: "name" with a value of your name, "age" with a value of your age, and "city" with a value of your city.

2. **Word Frequency Counter:**

Create a function that takes a string as input and returns a dictionary containing the frequency of each word in the string. Ignore case and punctuation. For example, for the input "Hello world. Hello Python.", the output should be `{'hello': 2, 'world': 1, 'python': 1}`.

3. **Dictionary Merging:**

Write a program that defines two dictionaries, `dict1` and `dict2`. Merge these dictionaries into a new one called `merged_dict` and print the result. If there are common keys, sum their values. For example:

```python

dict1 = {'a': 10, 'b': 20}

dict2 = {'b': 30, 'c': 40}

merged_dict = {...} # Your code here

# Output should be {'a': 10, 'b': 50, 'c': 40}

```

4. **Removing Duplicates:**

Create a function that takes a list of numbers as input and returns a dictionary with the unique numbers as keys and their frequencies as values. For example, for the input `[1, 2, 2, 3, 4, 4, 4]`, the output should be `{1: 1, 2: 2, 3: 1, 4: 3}`.

5. **Nested Dictionary Access:**

Define a nested dictionary representing a person's contact information with keys such as "name," "address," and "phone." Write a function that takes the person's name and a key as input and returns the corresponding value. Make sure to handle cases where the name or key is not present in the dictionary.