Python's string formatting tools annoy me. And what annoys me, eventually gets fixed, even if it's with an evil hack.

In Perl (and originally in Bourne Shell), you can write:

print "It is ${foo}!";

In Python up to 2.4, you would write:

print "It is %s!" % (foo,)

print "It is %(foo)s!" % {"foo":foo}

In Python 2.5 and later, there's a new formatter:

print "It is {foo}!".format(foo=foo)

In Python 3.0 and later, it's now:

print("It is {foo}!".format(foo=foo))

This is a mess. You can't even find the message in all that line noise, and the name is repeated 2 extra times. Printing several values is unmaintainable.

Hack #1: Use vars() to hide the redundant name assignment.

print("It is {foo}!".format(**vars()))
# **aDict expands the dict as keyword args

print("It is %(foo)s!" % vars())

Still a lot of noise, but foo is just pulled from local scope. Maybe I can hide that vars() assignment?

Hack #2:

print(fmt("It is {foo}!"))

Sweet! How did I do that? It is magic! But it's black, vile, corrupt magic, and it's about 120x slower than the ugly one (though still unnoticeably fast on modern hardware).

""">>>import inspect
>>>x=2
>>>fmt("{0} {x} {y}", 1, y=3)
'1 2 3'
"""
def fmt(s, *args, **kwargs):
	c_frame = inspect.getouterframes(inspect.currentframe(), 1)[1][0]
	c_args, c_varargs, c_varkw, c_locals = inspect.getargvalues(c_frame)
	d = dict(c_locals)
	if kwargs: d.update(kwargs)
	return s.format(*args, **d)