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Python
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Articles
- How to write a comment and comment out lines in Python
- Python docstring formats (styles) and examples
- Python indentation rules
- Valid variable names and naming rules in Python
- Python for loop (with range, enumerate, zip, and more)
- Python while loop (infinite loop, break, continue, and more)
- Break out of nested loops in Python
- How to use range() in Python
- Infinite iterators in Python (itertools.count, cycle, repeat)
- Python if statement (if, elif, else)
- What is "if __name__ == '__main__'" in Python
- Convert between bool (True/False) and other types in Python
- Conditional expression (ternary operator) in Python
- Chained comparison (a < x < b) in Python
- Difference between the == and is operators in Python
- Boolean operators in Python (and, or, not)
- Bitwise operators in Python (AND, OR, XOR, NOT, SHIFT)
- Arithmetic operators in Python (+, -, *, /, //, %, **)
- Get and check the type of an object in Python: type(), isinstance()
- Define and call functions in Python (def, return)
- How to return multiple values from a function in Python
- Default parameter values for functions in Python
- *args and **kwargs in Python (Variable-length arguments)
- List built-in objects with dir(__builtins__) in Python
- Lambda expressions in Python
- How to import modules, packages, functions, etc. in Python
- Check and add the module search path with sys.path in Python
- Command line arguments in Python (sys.argv, argparse)
- What is nan in Python (float('nan'), math.nan, np.nan)
- None in Python
- The pass statement in Python
- A tuple with one element requires a comma in Python
- Update tuples in Python (Add, change, remove items in tuples)
- Multiple assignment in Python: Assign multiple values or the same value to multiple variables
- How to use len() in Python
- How to use the key argument in Python (sorted, max, etc.)
- How to use all() and any() in Python
- Cumulative calculations with itertools.accumulate() in Python
- Duck typing with hasattr() and abstract base class in Python
- Check subclass and superclass in Python (issubclass, __bases__, etc.)
- The operator module in Python (itemgetter, attrgetter, methodcaller)
- Shallow and deep copy in Python: copy(), deepcopy()
- Take input from user with input() in Python
- Check Python version on command line and in script
- Check the versions of Python packages (libraries)
- Get the OS name and version in Python
- Get, set, and delete environment variables with os.environ in Python
- Get/set the recursion limit in Python (sys.getrecursionlimit, sys.setrecursionlimit)
- Keywords and reserved words in Python
- Copy and paste text to the clipboard with pyperclip in Python
- Guess MIME type from filename/URL with mimetypes in Python
- Read and write CSV files in Python
- Load, parse, serialize JSON files and strings in Python
- Measure execution time with timeit in Python
- Convert 1D array to 2D array in Python (numpy.ndarray, list)
- Method chaining across multiple lines in Python
- How to use pip (Install, update, uninstall packages)
- How to install Python packages with pip and requirements.txt
- List installed Python packages with pip list/freeze
- Try, except, else, finally in Python (Exception handling)
- The assert statement in Python
- How to ignore warnings in Python
- Read, write, and create files in Python (with and open())
- Create a directory with mkdir(), makedirs() in Python
- Delete a file/directory in Python (os.remove, shutil.rmtree)
- Move a file/directory in Python (shutil.move)
- Copy a file/directory in Python (shutil.copy, shutil.copytree)
- Check if a file/directory exists in Python (os.path.exists, isfile, isdir)
- Get the filename, directory, extension from a path string in Python
- Get a list of file and directory names in Python
- How to use glob() in Python
- Get and change the current working directory in Python
- Get the path of the current file (script) in Python: __file__
- Get the file/directory size in Python (os.path.getsize)
- Zip and unzip files with zipfile and shutil in Python
- How to use pathlib in Python
- Get the size (length, number of items) of a list in Python
- Find the index of an item in a list in Python
- The in operator in Python (for list, string, dictionary, etc.)
- Initialize a list of any size with specific values in Python
- Add an item to a list in Python (append, extend, insert)
- Remove an item from a list in Python (clear, pop, remove, del)
- Extract, replace, convert elements of a list in Python
- Remove/extract duplicate elements from list in Python
- Check if a list has duplicates in Python
- Extract common/non-common/unique elements from multiple lists in Python
- Compare lists in Python
- List comprehensions in Python
- Apply a function to items of a list with map() in Python
- Filter (extract/remove) items of a list with filter() in Python
- Unpack a tuple and list in Python
- How to start enumerate() at 1 in Python
- zip() in Python: Get elements from multiple lists
- Use enumerate() and zip() together in Python
- Sort a list, string, tuple in Python (sort, sorted)
- Sort a 2D list in Python
- Reverse a list, string, tuple in Python (reverse, reversed)
- Get the n-largest/smallest elements from a list in Python
- Random sample from a list in Python (random.choice, sample, choices)
- Shuffle a list, string, tuple in Python (random.shuffle, sample)
- Count elements in a list with collections.Counter in Python
- Convert between a list and a tuple in Python
- Transpose 2D list in Python (swap rows and columns)
- How to flatten a list of lists in Python
- Swap values in a list or values of variables in Python
- Cartesian product of lists in Python (itertools.product)
- How to use deque in Python (collections.deque)
- GROUP BY in Python (itertools.groupby)
- List vs. array vs. numpy.ndarray in Python
- Expand and pass a list and dictionary as arguments in Python
- Pretty-print with pprint in Python
- Sort a list of dictionaries by the value of the specific key in Python
- Extract specific key values from a list of dictionaries in Python
- Sort a list of numeric strings in Python
- Get image size (width, height) with Python, OpenCV, Pillow (PIL)
- Detect and read barcodes and QR codes with ZBar in Python
- Fractions (rational numbers) in Python
- Complex numbers in Python
- Set operations in Python (union, intersection, symmetric difference, etc.)
- Trigonometric functions in Python (sin, cos, tan, arcsin, arccos, arctan)
- Power and logarithmic functions in Python (exp, log, log10, log2)
- Find GCD and LCM in Python (math.gcd(), lcm())
- Calculate mean, median, mode, variance, standard deviation in Python
- Create a dictionary in Python ({}, dict(), dict comprehensions)
- Add and update an item in a dictionary in Python
- Merge dictionaries in Python
- Remove an item from a dictionary in Python (clear, pop, popitem, del)
- Add an item if the key does not exist in dict with setdefault in Python
- Check if a key/value exists in a dictionary in Python
- Get a value from a dictionary by key in Python
- Get keys from a dictionary by value in Python
- Iterate through dictionary keys and values in Python
- Change a key name in a dictionary in Python
- Swap keys and values in a dictionary in Python
- Get maximum/minimum values and keys in Python dictionaries
- Set operations on multiple dictionary keys in Python
- Round numbers with round() and Decimal.quantize() in Python
- Generate random numbers (int and float) in Python
- Get the absolute value with abs() and math.fabs() in Python
- Get quotient and remainder with divmod() in Python
- Get the fractional and integer parts with math.modf() in Python
- Check if a number is an integer in Python
- Integer (int) has no max limit in Python 3
- Maximum and minimum float values in Python
- Infinity (inf) in Python
- Check if the floating point numbers are close in Python (math.isclose)
- Sign function in Python (sign/signum/sgn, copysign)
- Round up/down decimals in Python (math.floor, math.ceil)
- Count the number of 1 bits in python (int.bit_count)
- Handle date and time with the datetime module in Python
- Get the current date and time in Python (datetime.now, date.today)
- Measure elapsed time and time differences in Python
- Convert between isoformat string and datetime in Python
- Convert between Unix time (Epoch time) and datetime in Python
- Get file timestamp in Python (os.stat, os.path.getmtime, and more)
- Create calendar as text, HTML, list in Python
- Get the number of days and weeks in a month in Python
- Determine, count, and list leap years in Python
- Create a string in Python (single/double/triple quotes, str())
- How to use print() in Python
- Format strings and numbers with format() in Python
- How to use f-strings in Python
- Get the length of a string (number of characters) in Python
- Concatenate strings in Python (+ operator, join, etc.)
- Replace strings in Python (replace, translate, re.sub, re.subn)
- Split a string in Python (delimiter, line break, regex, and more)
- Search for a string in Python (Check if a substring is included/Get a substring position)
- String comparison in Python (exact/partial match, etc.)
- Extract a substring from a string in Python (position, regex)
- Remove a substring from a string in Python
- Count characters or substrings in a string in Python
- Handle line breaks (newlines) in strings in Python
- Regular expressions with the re module in Python
- How to use regex match objects in Python
- Convert binary, octal, decimal, and hexadecimal in Python
- Convert a string to a number (int, float) in Python
- Check if a string is numeric, alphabetic, alphanumeric, or ASCII
- Pad strings and numbers with zeros in Python (Zero-padding)
- Right-justify, center, left-justify strings and numbers in Python
- Uppercase and lowercase strings in Python (conversion and checking)
- Write a long string on multiple lines in Python
- Wrap and truncate a string with textwrap in Python
- Raw strings in Python
- Convert between Unicode code point and character (chr, ord)
- Extract and replace elements that meet the conditions of a list of strings in Python
- Convert a list of strings and a list of numbers to each other in Python
- How to slice a list, string, tuple in Python
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