20 chapters of Python should be a foundation solid enough to let me start learning yet another language without mixing the new knowledge up. Well, at least I am gonna give it a try. So here’s what I found out while reading Programming Ruby.

When overriding a method in a subclass, the keyword super suffices on [...]

Package imports require you to put __init__.py files in each directory in the package chain.
The modifier as provides a means of neatly aliasing package paths in import statements with short names.

from-statements let you expose your code to the amout of namespace pollution you like:
from some_module import some_function (like use CGI qw(header); in Perl)
Symbol tables of modules are accessed through the dictionary named __dict__.

after sifting through some slides about The Cobra Programming Language, I get the impression that Cobra might be a language worth keeping in mind.

sys.modules is a dictionary that contains all loaded modules’ names as keys.

Anonymous functions are declared with lambda instead of def.
Lambda definitions are expressions and may therefore not contain if-statements and the like.
map(foo, list1, list2, list3) is like [foo(*tuple) for tuple in zip(list1, list2, list3)].
By using yield instead of return to provide a return value, you create a function that returns a generator object that returns one [...]

Perl
Python

my $x = 10;
sub foo
{
$x = 20;
}

x = 10
def foo():
global x
x = 20

Declaring a variable in a function as global is only necessary for reassignments, not for mere read-access.
def foo(x, y, z): pass
foo(10, 20, 30)
does the same as
[...]

A function definition may be put inside an if-block.
if DEBUG:
  def do_something():
    print ‘useful debug information’
    do_some_work()
else:
  def do_something():
    do_some_work()

Docstrings are available at runtime via the __doc__ attribute.
The reference count of any object is available via sys.getrefcount(object).

while and for loops may have an else block that is executed if the loop terminates naturally, that is, not by a break statement.
There is a no-op statement called pass.
Assignments to variables do not return the assigned value; they are statements, not expressions.
You can build your own iterables by implementing a next method that raises [...]