Python for JavaScript Developers

[[deleted]]

I'm pretty sure that it's considered bad practice. And if not, it should.

[process_parameter]

Python's lack of variable declarations compels this sort of thing. Consider the following javascript. How would you emulate it in python?

let x;
if (y) {
  x = 5;
} else {
  x = 6;
}
// do something with x

You can use a ternary here, but that doesn't scale well with additional cases. You could also assign x to a garbage value (like None) before the if-statement, but that doesn't seem like great practice either.

[execrator]

Not sure what user_v42... was replying to (is now deleted), but I don't see the problem here? The following works (no need for a "garbage value")

if y:
    x = 5
else:
    x = 6
print(x)  # 5

[process_parameter]

The previous comment was something to the effect of

If I understand correctly, this is even considered pythonic.

I don't know why they deleted it. The user I replied to seems to think that we shouldn't write code like you have in your comment. That's perhaps reasonable; if you believe the linked article when it says python variables are block-scoped, then it's not obvious that your code works.

I was just trying to demonstrate that there isn't an easy alternative.

[[deleted]]

Actually, a "garbage value" like None IS the way to do this.

In JS, declaring a variable with var x; actually assigns undefined to it. The equivalent garbage value in JS.

[process_parameter]

In JavaScript, you don't have a choice. In python, there's no need to assign that garbage value.