Add tech_docs/python/important_functions.md

tech_docs/python/important_functions.md

@@ -0,0 +1,48 @@
+Here are the most important Python functions to learn and master:
+
+## Built-in Functions
+1. **print()** - Output text and variables
+2. **input()** - Capture user input
+3. **len()** - Get the length of objects (strings, lists, etc.)
+4. **range()** - Generate sequences of numbers
+5. **type()** - Check the data type of an object
+6. **int(), float(), str(), bool()** - Type conversion functions
+7. **sum(), min(), max()** - Mathematical operations on iterables
+
+## String Methods
+1. **split()** - Convert string to list
+2. **join()** - Combine list elements into string
+3. **strip()** - Remove whitespace
+4. **replace()** - Substitute text
+5. **upper(), lower()** - Change case
+
+## List Methods
+1. **append()** - Add item to end
+2. **extend()** - Add multiple items
+3. **insert()** - Add item at specific position
+4. **remove()** - Delete by value
+5. **pop()** - Remove by index
+
+## Dictionary Methods
+1. **get()** - Retrieve value safely
+2. **keys(), values(), items()** - Access dictionary components
+3. **update()** - Merge dictionaries
+
+## File Operations
+1. **open()** - Access files
+2. **read(), write()** - File I/O operations
+3. **with** statement (context manager)
+
+## From Standard Libraries
+1. **datetime.datetime()** - Date/time handling
+2. **random.randint(), random.choice()** - Generate random values
+3. **os.path.join()** - File path manipulation
+4. **json.loads(), json.dumps()** - JSON processing
+5. **re.search(), re.findall()** - Regular expressions
+
+## From Third-Party Libraries
+1. **pandas.DataFrame()** - Data analysis
+2. **numpy.array()** - Numerical computing
+3. **matplotlib.pyplot.plot()** - Data visualization
+
+Mastering these functions will give you a solid foundation for most Python programming tasks.