Python, defined.

Outputs text or values to the console.

Use · Display results, debug variables, show messages.

print("Hello, Pynexa!")

Reads a line of text typed by the user from the keyboard.

Use · Collect user data interactively.

name = input("Your name: ")
print("Hi", name)

Returns the number of items in a string, list, tuple, dict, etc.

Use · Measure size of any sequence.

len("python")  # 6

Returns the data type of an object.

Use · Inspect what kind of value you're holding.

type(42)  # <class 'int'>

Creates a sequence of integers from start to stop (exclusive).

Use · Drive for-loops, generate numeric series.

for i in range(1, 6):
    print(i)

The four primitive types: whole number, decimal, text, true/false.

Use · Represent all basic values in Python.

x = 5
y = 3.14
z = "hi"
f = True

An ordered, mutable collection of items.

Use · Store sequences you may need to modify.

fruits = ["apple", "kiwi"]
fruits.append("mango")

An ordered, immutable collection of items.

Use · Fixed groupings, dictionary keys, function returns.

point = (3, 4)
x, y = point

Key-value pairs with fast lookup.

Use · Map labels to values (records, configs, lookups).

user = {"name": "Sky", "age": 17}
print(user["name"])

Unordered collection of unique items.

Use · Remove duplicates, fast membership tests.

s = {1, 2, 2, 3}  # {1, 2, 3}

Runs different blocks of code based on conditions.

Use · Make decisions in your program.

n = 7
if n > 0:
    print("positive")
elif n == 0:
    print("zero")
else:
    print("negative")

Repeats a block once for each item in a sequence.

Use · Iterate over lists, strings, ranges, files.

for c in "PYNEXA":
    print(c)

Repeats a block as long as a condition is True.

Use · Loop until something changes — input, game state, etc.

n = 5
while n > 0:
    print(n)
    n -= 1

Exits the nearest enclosing loop immediately.

Use · Stop searching once you've found what you want.

for x in range(10):
    if x == 4: break
    print(x)

Skips the rest of the current iteration and continues with the next.

Use · Ignore specific cases inside a loop.

for x in range(5):
    if x == 2: continue
    print(x)

Does nothing — a placeholder where a statement is required.

Use · Stub functions, classes, or empty blocks.

def todo():
    pass

Defines a reusable block of code that may take inputs and return a value.

Use · Organize code, avoid repetition, build APIs.

def square(x):
    return x * x

print(square(5))

Accept any number of positional / keyword arguments.

Use · Flexible function signatures, wrappers, decorators.

def show(*args, **kw):
    print(args, kw)

A small anonymous function written inline.

Use · Short one-off functions for sort/map/filter.

double = lambda x: x * 2
print(double(4))

Sends a value back from a function to the caller.

Use · Produce outputs from functions.

def add(a, b):
    return a + b

A blueprint that bundles data (attributes) and behavior (methods).

Use · Model real-world objects, build reusable types.

class Dog:
    def __init__(self, name):
        self.name = name
    def bark(self):
        print(self.name, "woof!")

Special method that initializes a new object.

Use · Set up object state when it's created.

class Point:
    def __init__(self, x, y):
        self.x, self.y = x, y

Reference to the current instance inside a method.

Use · Access instance attributes and other methods.

def name_of(self):
    return self.name

A class can derive attributes and methods from another class.

Use · Reuse and extend existing classes.

class Animal: pass
class Cat(Animal): pass

Run code that might fail and handle the error gracefully.

Use · Prevent crashes, recover from bad input or I/O.

try:
    x = int("abc")
except ValueError as e:
    print("bad:", e)

Manually throw an exception.

Use · Signal invalid state or arguments.

if n < 0:
    raise ValueError("must be >= 0")

Opens a file for reading or writing.

Use · Read text/CSV/JSON, save data to disk.

with open("note.txt", "w") as f:
    f.write("hi")

Automatically cleans up resources when a block exits.

Use · Files, locks, network connections.

with open("a.txt") as f:
    data = f.read()

Loads code from another module so you can use it.

Use · Reuse the standard library and 3rd-party packages.

import math
print(math.sqrt(16))

Imports specific names from a module.

Use · Pull just what you need without prefixing.

from random import randint
print(randint(1, 10))

Compact syntax to build a list from an iterable with an optional filter.

Use · Replace many short for-loops with one line.

squares = [x*x for x in range(6)]

Compact syntax to build a dictionary.

Use · Transform pairs into a lookup table.

sq = {x: x*x for x in range(5)}

Formatted string literal that embeds expressions inside { }.

Use · Readable string formatting.

name = "Sky"
print(f"Hello, {name}!")

Extract a portion of a sequence using [start:stop:step].

Use · Subsets of strings, lists, tuples.

nums = [0,1,2,3,4]
print(nums[1:4])  # [1,2,3]

Math functions: sqrt, sin, cos, log, pi, etc.

Use · Scientific or numeric computations.

import math
print(math.pi)

Generates pseudo-random numbers and choices.

Use · Games, sampling, shuffling.

import random
print(random.choice(["a","b","c"]))

Work with dates and times.

Use · Timestamps, age, scheduling.

from datetime import date
print(date.today())

Read and write JSON data.

Use · Configs, APIs, persistence.

import json
print(json.dumps({"a": 1}))