Rated as one of the Best Python Tutorial in 2025. This quick refresher is targeted for those who have studied python as language before and are just looking for quick refresher and more like a crash course, to get back into the game of programming again. Hope you like this Python Tutorial, feel free to drop in comments and let me know if you would like any content to be modified or added.
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Best Python Tutorial
Python Collections
List Data Type
- Highly Flexible and powerful data structures
- Like Tuples, can hold any kind of object, BUT are mutable in nature, i.e. you can modify their content.
- You can unpack a list and assign its items to discrete variable
- Expressed as comma separated sequence of objects enclosed in square brackets
- You can create an empty list by specifying square brackets or using default value of list() type function
- You can initialize a list by using list of values or build them programmaticallyexpression
- Empty lists are treated as False in Boolean
- Elements are accessed using numeric index
Dictionary Data Type
- Elements are accessed using key-value pair
- It’s elements are non-ordered sequence of key-value pair
- Key can be any immutable value, including a Tuple. It must be unique.
- Value can be any Python object, including another dictionary or list
- Lookup times are very fast and internally they use memory efficiently
- Useful where keys are not sequential, as Python uses hashing to map the keys into a sparse data structures
- Dictionary elements are comma separated key:value pair, with key and value separated by colon and within curly braces {}
- Dictionary can be created using empty pair of braces or by using default value of dict()
- Dictionary is by nature Unsorted.
- OrderedDict module of Collections class maintains the order of insertion should that be required
- defaultDict class of Collections module also provides a default value when non-existent key is used. It also creates a new element for the given key with the default value.
- Empty Dictionaries are treated as False in Boolean expressions
Sets Data Type
- Used where a unique group of elements is required.
- Think of Sets as Dictionary data types, only with keys but no corresponding values
- ‘set’ elements must be immutable and unique.
- default value is empty set, use set() to initialize.
- set() accepts any form of collection as it’s elements.
- Passing Dictionary to Set will make it lose all the values and will keep its keys only.
- frozenset() – immutable and read only set. Supports only limited set of operations from a regular set.
- set elements are separated by comma, within curly braces.
- It does not have any inherent order, however sorted() returns an ordered list of elements.
- Empty sets are treated as False in Boolean expressions.
