Python will throw an error if you use any the following keywords as a variable name.
See this page for more details: Keywords.
None False True and as assert async await break class continue def del elif else except finally for from global if import in is lambda nonlocal not or pass raise return try while with yield

You should avoid using the following functions names in your code, neither as a variable name nor as a function name.
See this page for more details: Built-in Functions.
__import__() abs() aiter() all() anext() any() ascii() bin() bool() breakpoint() bytearray() bytes() callable() chr() classmethod() compile() complex() delattr() dict() dir() divmod() enumerate() eval() exec() filter() float() format() frozenset() getattr() globals() hasattr() hash() help() hex() id() input() int() isinstance() issubclass() iter() len() list() locals() map() max() memoryview() min() next() object() oct() open() ord() pow() print() property() range() repr() reversed() round() set() setattr() slice() sorted() staticmethod() str() sum() super() tuple() type() vars() zip()

Variables names:

• Variables names can contain only letters, numbers, and/or underscores.
• Variables names can't start with a number.

Define a variable: a = "Hello" print(a) # ==> Hello
Multiple assignment: x, y , z = 1, 2, 3 a, b , c = 'hello', 'python', '!'

To comment a line or part of a line, use the hash mark character (#). #this is a comment x = 1 # this another comment

Integers: 1, 2, ...
Floats, 1.0, 2.0, ...
Operations: +, -, *, /, \%, ** (exponents)

Using underscores between digits in numeric literals: i = 1_000_000 print(i) # ==> 1000000
Modulo operator: i = 5 % 2 print(i) # ==> 1

a = "This is a valid string" b = "This is a 'valid' string" c = 'This is a valid string' d = 'This is a "valid" string'
Changing string case: #The title() function changes each word of a string in title case (begins with a capital letter) print('hello python'.title()) # ==> Hello Python #The upper() function changes a string to all uppercase print('hello python'.upper()) # ==> HELLO PYTHON #The lower() function changes a string to all lowercase print('HELLO PYTHON'.lower()) # ==> hello python
Formating a string (f-strings):
To use a variable or a function inside a string, place the letter f before opening quotation mark.
Inside the string put any variable or function you want to use and surround it with braces. x='hello' y='python' z=f'message: {x} {y.title()}' print(z) # ==> message: hello Python
Adding whitespace to strings with tabs (\t) or newlines (\n): print("hello\n\n\t\tpython") hello python
Stripping whitespace: x = ' hello python ' #use strip() function to remove whitespace from the beginning (left) and the end (right) of a string. print(f'"{x.strip()}"') # ==> "hello python" #use lstrip() function to remove whitespace from the beginning (left) of a string. print(f'"{x.lstrip()}"') # ==> "hello python " #use rstrip() function to remove whitespace from the end (right) of a string. print(f'"{x.rstrip()}"') # ==> " hello python"
Removing prefixes and suffixes: x = "hello python" print(f'"{x.removeprefix("hello")}"') # ==> " python" print(f'"{x.removesuffix("python")}"') # ==> "hello "
Split words: words = 'hello python 3'.split() print(f'Number of words: {len(words)}') # ==> Number of words: 3 for word in words: print(f'word: {word} | length: {len(word)}') Number of words: 3 word: hello | length: 5 word: python | length: 6 word: 3 | length: 1
Split lines: lines = 'hello\n\n\t\tpython'.splitlines() for line in lines: print(f'line: {line.strip()}') line: hello line: line: python
Convert string to int: i = int('1') print(i) # ==> 1

Parsing a string date using a specific format: from datetime import datetime date = datetime.strptime('05/08/2023 01-16-26 PM', '%d/%m/%Y %I-%M-%S %p') print(date) #==> 2023-08-05 13:16:26
Date and time formating:

• %d: Day of the month (01 - 31)
• %m: Month (01 - 12)
• %y: Two-digit year (23, ...)
• %Y: Four-digit year (2023, ...)
• %I: Hour, in 12-hour format (00 - 12)
• %H: Hour, in 24-hour format (00 - 23)
• %p: AM|PM
• %M: Minutes (00 - 59)
• %S: Seconds (00 - 59)
• %A: Weekday name (Monday, ...)
• %B: Month name (January, ...)