Python vs Ruby

Both Python and Ruby are supported by .NET. People may frustrated which one should be learn. Here are some differences between the two.

1) Ruby has blocks; Python does not.

2) Python has functions; Ruby does not. In Python, you can take any function or method and pass it to another function. In Ruby, everything is a method, and methods can't be directly passed. Instead, you have to wrap them in Proc's to pass them.

3) Ruby and Python both support closures, but in different ways. In Python, you can define a function inside another function. The inner function has read access to variables from the outer function, but not write access. In Ruby, you define closures using blocks. The closures have full read and write access to variables from the outer scope.

4) Python has list comprehensions, which are pretty expressive. For example, if you have a list of numbers, you can write


[x*x for x in values if x > 15]
to get a new list of the squares of all values greater than 15. In Ruby, you'd have to write the following:

values.select {|v| v > 15}.map {|v| v * v}
The block works very much like a function being passed to collection.each. If you were to do the same thing in Python, you'd have to define a named inner function and then pass that to the collection each method (if list supported this method):

def some_operation(value):
...

collection.each(some_operation)
That doesn't flow very nicely. So, typically the following non-functional approach would be used in Python:

for value in collection:
...


10) Using resources in a safe way is quite different between the two languages. Here, the problem is that you want to allocate some resource (open a file, obtain a database cursor, etc), perform some arbitrary operation on it, and then close it in a safe manner even if an exception occurs.

In Ruby, because blocks are so easy to use (see #9), you would typically code this pattern as a method that takes a block for the arbitrary operation to perform on the resource.

In Python, passing in a function for the arbitrary action is a little clunkier since you have to write a named, inner function (see #9). Instead, Python uses a "with" statement for safe resource handling. See How do I correctly clean up a Python object? for more details.