7️⃣

# 9.7 Practice

## Practice

### Characters

Write a Python program to create a dictionary from a string where the keys are the characters and the values are the frequency of the characters.
Your program should ask the user to enter a string, convert it into the dictionary described above, and print the resulting dictionary.
NOTE: Using "collections.Counter" is not allowed for this problem.
Example output:
``````Enter a string:  hello244oh
{'h' : 2, 'e' : 1, 'l' : 2, 'o' : 2, '2' : 1, '4' : 2}``````

### Catalog

Write a program that asks the user whether they'd like to add, delete, or clear the entries in a store catalog.
After they perform some action, the program should display the updated dictionary in the following format:
``````item1 : price1
item2 : price2
(etc)``````
Keep asking them if they'd like to add, delete, or clear entries until they enter "q".
Possible actions:
• If they enter "add" : Ask them to enter an item. Ask them to enter a price. The item should be the key, and the price should be the value in the dictionary
• If they enter "delete" : Ask them which item they'd like to delete.
• If they enter "clear" : Clear all the entries from the dictionary.
• If they enter "q" : Display the final dictionary and end the program

### Word

Store words (keys) and definitions (values) in a dictionary in random order. Then, ask the user to input a word. If the word is in the dictionary, use it to display the definition. Otherwise, print out a message saying that the word is not there.
Display the entire dictionary at the end in the following format:
``````word1 : definition1
word2 : definition2
(etc)``````

### Participation Grade

💡
Warning! This can be challenging
A teacher is given a list of students. The number of occurrences of a student's name in the list is the number of times the student participated this week. If a student has 8 or more participations, they get an A. If a student has between 4 and 7 participations, they get a B. If a student has more than 0 but less than 4 participations, the student gets a C.
Make a dictionary with the keys as the student's name and the values as the corresponding student's letter grade. Print the dictionary.

## Next Section

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