PART 7 - Python Tutorial | Dictionaries In Python With Examples
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The document explains dictionaries in Python, describing them as collections of key-value pairs with mutable properties. It covers how to define, access, modify, and loop through dictionaries, as well as techniques like nesting and storing multiple dictionaries. Examples include counting character frequencies and mapping countries to capitals.
PART 7 - Python Tutorial | Dictionaries In Python With Examples
- 1. PART 7 DICTIONARIES IN PYTHON • WANT TO LEARN PYTHON PROGRAMMING? (SUBTITLES) • SUBSCRIBE • TELEGRAM – FreeCodeSchool • Twitter – shivammitra4 • LinkedIn – shivammitra • Link in description
- 2. WHAT IS A DICTIONARY ? Alphabetical order
- 3. DICTIONARY IN PYTHON • A collection of key-value pairs • Each key is mapped to a value. • Use key to access the value mapped to it • Keys -> Numbers, Strings • Values -> Any data type like number, strings, lists, dictionaries etc.
- 4. DEFINING A DICTINOARY IN PYTHON • A dictionary is wrapped in braces • Series of key-value pairs inside the braces • Every key is connected to its value with colon • Key-value pairs are separated by comma • You can store as many key-value pairs you want
- 5. ACCESSING ELEMENT IN A DICTIONARY Similar to list but access using key here than index
- 6. A DICTIONARY WITH MULTIPLE KEYS
- 7. ADDING NEW KEY-VALUE PAIRS
- 9. STARTING WITH AN EMPTY DICTIONARY
- 10. MODIFYING VALUES IN A DICTIONARY
- 11. DICTIONARIES ARE MUTABLE • One can add, delete and modify key-value pairs in a dictionary • Key or values can be mutable or immutable depending on their type • Strings -> immutable • Numbers, lists -> mutable
- 14. USING get() TO ACCESS VALUES TRY RUNNING THIS CODE
- 17. WRITE A PROGRAM TO COUNT THE FREQUENCY OF EACH CHARACTER IN A GIVEN STRING. INPUT – ‘mississippi’ Output: Count of each character in this word. ‘m’ -> 1
- 18. LOOPING THROUGH A DICTIONARY • A dictionary can contain millions of entries • Looping over all • Key-value pairs • Keys • Values
- 19. LOOPING THROUGH ALL KEY-VALUE PAIRS key, value -> k,v
- 20. HOW DOES LOOPING WORKS ?
- 21. TRY LOOPING THROUGH COUNTRY-CAPITAL EXAMPLE
- 22. LOOPING THROUGH DICTIONARY KEYS
- 25. LOOPING THROUGH KEYS IN AN ORDER Print keys in reverse order
- 26. LOOPING THROUGH ALL VALUES IN A DICTIONARY Print the values in order
- 27. NESTING • Storing multiple dictionary in a list • List of items as a value in a dictionary • A dictionary inside another dictionary • This is called nesting.
- 28. A LIST OF DICTIONARIES
- 29. A MORE REALISTIC EXAMPLE • Store the (number->square of number) mapping for numbers 1 to 5
- 30. A LIST IN A DICTIONARY
- 31. A DICTIONARY IN A DICTIONARY
- 33. USER INPUT AND WHILE LOOPS