Materials for the print() guide

python-print/README.md

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+# Your Guide to the Python print() Function
+
+This folder contains sample code for the Real Python tutorial [Your Guide to the Python print() Function](https://realpython.com/python-print/).

python-print/ansi.py

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+def esc(*codes):
+    return f"\033[{';'.join(str(code) for code in codes)}m"
+
+
+print(esc(31, 1, 4) + "really" + esc(0) + " important")

python-print/calculator.py

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+import readline  # noqa
+
+print('Type "help", "exit", "add a [b [c ...]]"')
+while True:
+    command, *arguments = input("~ ").split(" ")
+    if len(command) > 0:
+        if command.lower() == "exit":
+            break
+        elif command.lower() == "help":
+            print("This is help.")
+        elif command.lower() == "add":
+            print(sum(map(int, arguments)))
+        else:
+            print("Unknown command")

python-print/countdown.py

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+import time
+
+num_seconds = 3
+for countdown in reversed(range(num_seconds + 1)):
+    if countdown > 0:
+        print(countdown, end="...", flush=True)
+        time.sleep(1)
+    else:
+        print("Go!")

python-print/custom_class.py

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+class Person:
+    def __init__(self, name, age):
+        self.name = name
+        self.age = age
+
+    def __str__(self):
+        class_name = type(self).__name__
+        return f"{class_name}(name={self.name!r}, age={self.age!r})"
+
+
+jdoe = Person("John Doe", 42)
+print(jdoe)

python-print/morse_code.py

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+# flake8: noqa
+
+from time import sleep
+
+speed = 0.1
+
+
+def signal(duration, symbol):
+    sleep(duration)
+    print(symbol, end="", flush=True)
+
+
+dot = lambda: signal(speed, "·\a")
+dash = lambda: signal(3 * speed, "−\a")
+symbol_space = lambda: signal(speed, "")
+letter_space = lambda: signal(3 * speed, "")
+word_space = lambda: signal(7 * speed, " ")
+
+while True:
+    dot()
+    symbol_space()
+    dot()
+    symbol_space()
+    dot()
+    letter_space()
+
+    dash()
+    symbol_space()
+    dash()
+    symbol_space()
+    dash()
+    letter_space()
+
+    dot()
+    symbol_space()
+    dot()
+    symbol_space()
+    dot()
+    word_space()

python-print/progress.py

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+from time import sleep
+
+
+def progress(percent=0, width=30):
+    left = width * percent // 100
+    right = width - left
+    print(
+        "\r[",
+        "#" * left,
+        " " * right,
+        "]",
+        f" {percent:.0f}%",
+        sep="",
+        end="",
+        flush=True,
+    )
+
+
+for i in range(101):
+    progress(i)
+    sleep(0.1)

python-print/snake.py

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+import curses
+import time
+
+
+def main(screen):
+    curses.curs_set(0)  # Hide the cursor
+    screen.nodelay(True)  # Don't block I/O calls
+
+    directions = {
+        curses.KEY_UP: (-1, 0),
+        curses.KEY_DOWN: (1, 0),
+        curses.KEY_LEFT: (0, -1),
+        curses.KEY_RIGHT: (0, 1),
+    }
+
+    direction = directions[curses.KEY_RIGHT]
+    snake = [(0, i) for i in reversed(range(20))]
+
+    while True:
+        screen.erase()
+
+        # Draw the snake
+        screen.addstr(*snake[0], "@")
+        for segment in snake[1:]:
+            screen.addstr(*segment, "*")
+
+        # Move the snake
+        snake.pop()
+        snake.insert(0, tuple(map(sum, zip(snake[0], direction))))
+
+        # Change direction on arrow keystroke
+        direction = directions.get(screen.getch(), direction)
+
+        screen.refresh()
+        time.sleep(0.1)
+
+
+if __name__ == "__main__":
+    curses.wrapper(main)

python-print/spinning_wheel.py

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+from itertools import cycle
+from time import sleep
+
+for frame in cycle(r"-\|/-\|/"):
+    print("\r", frame, sep="", end="", flush=True)
+    sleep(0.2)

python-print/test_print.py

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+from unittest import TestCase
+from unittest.mock import patch
+
+
+class TestPrint(TestCase):
+    @patch("builtins.print")
+    def test_print(self, mock_print):
+        print("Not a real print()")
+        mock_print.assert_called_with("Not a real print()")
+
+    @patch("builtins.print")
+    def test_greet(self, mock_print):
+        greet("John")
+        mock_print.assert_called_with("Hello, John!")
+
+
+def greet(name):
+    print(f"Hello, {name}!")

python-print/thread_safe_print.py

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+import threading
+
+lock = threading.Lock()
+
+
+def thread_safe_print(*args, **kwargs):
+    with lock:
+        print(*args, **kwargs)

python-print/threads_simulation.py

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+import sys
+from random import random
+from threading import Thread, current_thread
+from time import sleep
+from unittest.mock import patch
+
+write = sys.stdout.write
+
+
+def slow_write(text):
+    sleep(random())
+    write(text)
+
+
+def task():
+    thread_name = current_thread().name
+    for letter in "ABC":
+        # print(f"[{thread_name} {letter}]")
+        print(f"[{thread_name} {letter}]\n", end="")
+
+
+with patch("sys.stdout") as mock_stdout:
+    mock_stdout.write = slow_write
+    for i in range(1, 4):
+        Thread(target=task, name=f"Thread-{i}").start()