Python 1.4: What's New, Release History & Support Lifecycle

What Is New in Python 1.4

Python 1.4 introduced keyword arguments in function calls, access control via __getattr__/__setattr__, built-in complex number support, and the __repr__ / __str__ distinction. Python 1.4 also refined the exception hierarchy and improved the standard library significantly. It was the first Python version to get serious traction beyond academic and research circles.

Key Features in Python 1.4

Keyword Arguments and **kwargs

Python 1.4 added the ability to call functions using keyword arguments (func(name="Alice")) and to accept an arbitrary keyword argument dictionary with **kwargs. These features enabled more flexible and readable APIs and are still cornerstones of Python's function calling convention.

def configure(host, port=8080, **options):
    print(f"host={host}, port={port}, extras={options}")

configure("localhost", port=9090, debug=True, timeout=30)
# host=localhost, port=9090, extras={'debug': True, 'timeout': 30}

Complex Number Type

Python 1.4 added a built-in complex type with literal syntax 3+2j (note: j not i, to avoid confusion with the identifier i). Complex numbers support all arithmetic operations and have .real and .imag attributes.

z1 = 3 + 2j
z2 = 1 - 1j
print(z1 + z2)   # (4+1j)
print(z1 * z2)   # (5-1j)
print(z1.real)   # 3.0
print(z1.imag)   # 2.0
print(abs(z1))   # 3.605... (modulus)

__repr__ vs __str__

Python 1.4 formalized the distinction: __repr__ should return an unambiguous, ideally eval-able representation for developers; __str__ should return a human-readable representation. When only __repr__ is defined, Python falls back to it for str(). The convention is: if repr output is valid Python, then eval(repr(obj)) == obj.

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

    def __repr__(self):
        return f"Point({self.x!r}, {self.y!r})"

    def __str__(self):
        return f"({self.x}, {self.y})"

p = Point(1, 2)
print(repr(p))  # Point(1, 2)  -- developer view
print(str(p))   # (1, 2)       -- user view