Python

Loops

A for loop:

# Syntax for iterating over elements in a collection (e.g., list, tuple, string):
for item in collection:
    # Code block executed for each item

# Syntax for iterating over a range of numbers:
for i in range(start, stop, step):
    # Code block executed for each value in the range

A while loop:

# Syntax for a while loop:
while condition:
    # Code block executed as long as the condition is true

Variable assignment

# Syntax for variable assignment:
variable_name = value

Functions

# Syntax for defining a function:
def function_name(parameter1, parameter2, ...):
    # Code block defining the function's behavior
    return result

String interpolation

# Syntax for f-string interpolation:
variable = 'world'
message = f'Hello, {variable}!'
print(message)  # Output: Hello, world!

Multiline strings

# Syntax for multiline strings:
multiline_string = '''
This is a multiline string.
It can span multiple lines.
'''

File I/O

# Syntax for reading from a file:
with open('filename.txt', 'r') as file:
    content = file.read()

# Syntax for writing to a file:
with open('output.txt', 'w') as file:
    file.write('Hello, world!')

HTTP requests

# Syntax for making an HTTP GET request:
import requests

response = requests.get('https://api.example.com/data')
data = response.json()  # Assuming the response contains JSON data

Arrays (Lists)

# Creating a list:
my_list = [1, 2, 3, 4, 5]

# Accessing elements:
print(my_list[0])  # Output: 1

# Slicing:
print(my_list[1:4])  # Output: [2, 3, 4]

# Modifying elements:
my_list[2] = 10
print(my_list)  # Output: [1, 2, 10, 4, 5]

# Appending elements:
my_list.append(6)
print(my_list)  # Output: [1, 2, 10, 4, 5, 6]

Dictionaries (Maps)

# Creating a dictionary:
my_dict = {'name': 'John', 'age': 30, 'city': 'New York'}

# Accessing elements:
print(my_dict['name'])  # Output: John

# Modifying elements:
my_dict['age'] = 35
print(my_dict)  # Output: {'name': 'John', 'age': 35, 'city': 'New York'}

# Adding new key-value pairs:
my_dict['occupation'] = 'Engineer'
print(my_dict)  # Output: {'name': 'John', 'age': 35, 'city': 'New York', 'occupation': 'Engineer'}

Tuples

These are immutable. They're good for things like coordinates.

# Creating a tuple:
my_tuple = (1, 2, 3)

# Accessing elements:
print(my_tuple[0])  # Output: 1

# Attempting to modify elements (will raise an error):
# my_tuple[1] = 10  # TypeError: 'tuple' object does not support item assignment

# Attempting to append elements (will raise an error):
# my_tuple.append(4)  # AttributeError: 'tuple' object has no attribute 'append'

List Comprehensions

These are fun ways to create lists based on existing lists.

# Creating a list comprehension
old_list = [1, 2, 3]
new_list = [x * 2 for x in old_list]
print(new_list)  # Output: [2, 4, 6]

# Creating a list comprehension with conditionals
even_numbers = [x for x in range(10) if x % 2 == 0]
print(even_numbers)  # Output: [0, 2, 4, 6, 8]

N Arguments

When passing multiple arguments to a function, you can use args and kwargs to pass an indeterminate number.

For example:

# Example of using args
def use_positional(*args):
    print(f"Positional arguments: {args}")

# Output of use_positional(1, 2, 3): "Positional arguments: (1, 2, 3)"

# Example of using kwargs
def use_keyword(**kwargs):
    print(f"Keyword arguments: {kwargs})

# Output of use_keyword(name="Bob", age=30): "Keyword arguments: {'name': 'Bob', 'age': 30}"