Materials for Python bytearray

python-bytearray/README.md

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+# Python's Bytearray: A Mutable Sequence of Bytes
+
+This folder contains code associated with the Real Python tutorial [Python's Bytearray: A Mutable Sequence of Bytes](https://realpython.com/python-bytearray/).

python-bytearray/creation.py

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+WIDTH = 71
+
+print(" Empty ".center(WIDTH, "="))
+print(f"{bytearray() = }")
+print(f"{bytearray(0) = }")
+print(f"{bytearray([]) = }")
+print(f"{bytearray(b"") = }\n")
+
+print(" Zero-filled ".center(WIDTH, "="))
+print(f"{bytearray(5) = }\n")
+
+print(" From an iterable of integers ".center(WIDTH, "="))
+print(f"{bytearray([65, 66, 67]) = }")
+print(f"{bytearray(range(3)) = }\n")
+
+print(" From a bytes-like object ".center(WIDTH, "="))
+print(f"{bytearray(b"Espa\xc3\xb1ol") = }\n")
+
+print(" From a string ".center(WIDTH, "="))
+print(f"{bytearray("Español", "utf-8") = }")
+print(f"{bytearray("Español", "ascii", errors="ignore") = }")
+print(f"{bytearray("Español", "ascii", errors="replace") = }\n")
+
+print(" From hexadecimal digits".center(WIDTH, "="))
+print(f"{bytearray.fromhex("30 8C C9 FF") = }")

python-bytearray/introspection.py

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+def main():
+    print(
+        "Mutator methods in bytearray:",
+        sorted(public_members(bytearray) - public_members(bytes)),
+    )
+    print(
+        "Special methods in bytearray:",
+        sorted(magic_members(bytearray) - magic_members(bytes)),
+    )
+    show_string_members()
+
+
+def public_members(cls):
+    return {name for name in dir(cls) if not name.startswith("_")}
+
+
+def magic_members(cls):
+    return {name for name in dir(cls) if name.startswith("__")}
+
+
+def show_string_members():
+    print("String members in bytearray:")
+    for i, name in enumerate(
+        sorted(
+            name
+            for name in set(dir(bytearray)) & set(dir(str))
+            if not name.startswith("_")
+        ),
+        start=1,
+    ):
+        print(f"({i:>2}) .{name}()")
+
+
+if __name__ == "__main__":
+    main()

python-bytearray/mutation.py

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+WIDTH = 71
+
+print(">>> pixels = bytearray([48, 140, 201, 252, 186, 3, 37, 186, 52])")
+print(">>> list(pixels)")
+pixels = bytearray([48, 140, 201, 252, 186, 3, 37, 186, 52])
+print(list(pixels))
+
+print("\n" + " Item assignment ".center(WIDTH, "="))
+print(
+    """\
+>>> for i in range(len(pixels)):
+...     pixels[i] = 255 - pixels[i]
+..."""
+)
+for i in range(len(pixels)):
+    pixels[i] = 255 - pixels[i]
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Slice assignment ".center(WIDTH, "="))
+print(">>> pixels[3:6] = (0, 0, 0)")
+pixels[3:6] = (0, 0, 0)
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Slice deletion ".center(WIDTH, "="))
+del pixels[3:6]
+print(">>> del pixels[3:6]")
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Item deletion ".center(WIDTH, "="))
+del pixels[3]
+print(">>> del pixels[3]")
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Item popping ".center(WIDTH, "="))
+print(">>> fourth_byte = pixels.pop(3)")
+print(">>> last_byte = pixels.pop()")
+fourth_byte = pixels.pop(3)
+last_byte = pixels.pop()
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Value removal ".center(WIDTH, "="))
+print(">>> pixels.remove(115)")
+pixels.remove(115)
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Clearing all items ".center(WIDTH, "="))
+print(">>> pixels.clear()")
+pixels.clear()
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Appending an item ".center(WIDTH, "="))
+print(">>> pixels.append(65)")
+print(">>> pixels.append(67)")
+pixels.append(65)
+pixels.append(67)
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Inserting an item ".center(WIDTH, "="))
+print(">>> pixels.insert(1, 66)")
+pixels.insert(1, 66)
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Extending the bytearray ".center(WIDTH, "="))
+print(">>> pixels.extend((1, 2, 3))")
+pixels.extend((1, 2, 3))
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Reversal ".center(WIDTH, "="))
+print(">>> pixels.reverse()")
+pixels.reverse()
+print(">>> list(pixels)")
+print(list(pixels))
+
+print("\n" + " Making a copy ".center(WIDTH, "="))
+print(">>> pixels_copy = pixels.copy()")
+pixels_copy = pixels.copy()
+print(">>> list(pixels)")
+print(list(pixels))