collection.each(lambda x:
      ...
      ...
    )

Or if the language doesn't require () to call a method, and uses `do` instead of `lambda`:

    collection.each do x:
       ...
       ...

If it's not the first argument:

    map(lambda x:
      ...
      ...
    , collection)

Yes this is ugly, but using a multi line anonymous function in the middle of an argument list will always be ugly.

in Python, it works like:

  foo(a, b, lambda x: x+2)

or

  foo2(a, b, foo):
      foo() # this is like js

The lambda is closed by the next ) or ,

Right, but you can't have multi-line anonymous functions, which are pleasant to use in Ruby and JavaScript.

True, but you can just write a non-anyonymous function in the current scope, which can be passed as boo or called as boo():

  def test():
    def boo(x):
      x += 2
      x += 3
      return x
    something_else(boo, 33, "hi")

  test()

This is equivalent to how procs are often used in Ruby...