Comment by creata 17 hours ago
The Ruby syntax doesn't seem that different to many other languages. For example:
xs.filter(x => x & 1).sort().join(", ") // JavaScript
xs & filter odd & sort & map show & intercalate ", " -- Haskell
> ... confusing as hell to "newcomers". For example, when a list comprehension has multiple `for`s, what order are they nested in?
I get that this is just a rhetorical question to make a point about newcomers, and I do agree it's not immediately obvious, but for the record: you can imagine any "if"s and "for"s in a list comprehension are nested statements in the same order. So, for example, this:
l = [
y.foo()
for x in my_list
if x.blah() > 7
for y in x.ys()
]
l = []
for x in my_list:
if x.blah() > 7:
for y in x.ys():
l.append(y.foo())
>Python seems to be the odd one out. Imo, its list comprehensions are confusing as hell to "newcomers". For example, when a list comprehension has multiple `for`s, what order are they nested in?
The order is mentioned right in the docs, for Python 3:
https://docs.python.org/3/tutorial/datastructures.html#list-...
>Note how the order of the for and if statements is the same in both these snippets.
And it is mentioned even more clearly in corresponding section in the Python 2 docs - last I checked, years ago,
Update: IOW, the nested list comprehension syntax is confusing only to newcomers or even experienced devs who are lazy or stupid enough to not read the docs for the language feature they want to use, before using it, IOW, "winging it", whether to try to seem cool or due to peer pressure or other reasons, all of which are stupid ones, even in the short term, because the cost is higher than the benefit in most cases.
Those both seem a little bit more consistent than the Ruby example, however. To understand the JS example for example, you only need know that to call a method on an object, you do `object.method(arguments)`, and this is chained in a straightforward manner, with methods called on the returned values left to right. Ditto for the Haskell example. Maybe the Ruby one does the same thing, but even in this extremely simple example, we still have two different ways of doing the same thing.
For Python, you don't really have to use list comprehensions in the place of multiple for loops, you can sacrifice the brevity afforded to write the same thing in a more easily understandable fashion.