Course Content
Introduction to Python
Introduction to Python
2. Variables and Types in Python
How to Store Numbers in PythonPython Naming Rules for VariablesHow to Work with Variables in PythonData Types in PythonChallenge: Converting Kilometers to MilesStore Text with Strings in PythonString Indexing in PythonNegative Indexing and String Length in PythonString Slicing in PythonChallenge: Retrieving Letters from StringString Concatenation in Python
3. Conditional Statements in Python
Boolean Data Type in PythonChallenge: Working with Comparison OperatorsHow to Combine Conditions in PythonChallenge: Working with Logical OperatorsMembership Operators and Type Comparisons in PythonHow to Use if/else Expressions in PythonChallenge: Running a Grocery StoreChallenge: Creating Odd and Even Logicif/elif/else ExpressionsChallenge: Running Grocery Store ExtendedChallenge: Weather Adviser
4. Other Data Types in Python
Python ListsCommon List Methods in PythonChallenge: Updating ListNested Lists in PythonChallenge: Retrieving Information from Nested ListPython TuplesCommon Tuple Methods in PythonChallenge: Updating TupleNested Tuples in PythonChallenge: Retrieving Information from Nested TuplePython DictionariesChallenge: Creating DictionaryCommon Dictionary Methods in PythonChallenge: Updating Dictionary
6. Functions in Python
Built-in Functions in PythonChallenge: Converting HeightsHow to Create Functions in PythonsChallenge: Writing First FunctionUse of if/else Statements in Python FunctionsChallenge: Identifying Positive Values Functions Without Return in PythonChallenge: Creating Logging FunctionModifying Functions in PythonChallenge: Updating Logic of the FunctionLambda Functions in PythonChallenge: Creating Lambda Function
Python Dictionaries
A dictionary is a data structure that stores values using keys, which can be strings, numbers, tuples, or other immutable types. Dictionaries organize data into key-value pairs, making them a powerful tool for efficient data retrieval.
- You can use any immutable type as a dictionary key;
- Tuples can serve as keys, but only if they contain strings, numbers, or other tuples;
- A dictionary cannot have duplicate keys each key must be unique.
- Dictionaries are enclosed within curly brackets
{}.
If you want to store information about different countries, you can use country names as dictionary keys, with values stored as tuples.
# Create dictionary countries_dict = {'USA': (9629091, 331002651), 'Canada': (9984670, 37742154), 'Germany': (357114, 83783942)} # Printing dictionary print(countries_dict)
You access dictionary values using their keys. If the key is a string as in our example, make sure to enclose it in quotation marks. Similar to indexing lists or tuples, you place the key inside square brackets to fetch the corresponding value.
# Dictionary countries_dict = {'USA': (9629091, 331002651), 'Canada': (9984670, 37742154), 'Germany': (357114, 83783942)} # Information about Canada print(countries_dict["Canada"])
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Section 4. Chapter 11
