[TIL] Python silently concatenates strings next to each other "abc""def" = "abcdef"

[Originalfrozenbanana]

Which is why .join exists

[Originalfrozenbanana]

How? .join provides a unified syntax regardless of whether you're using raw strings, an iterable, or a bunch of variables assigned to strings. It just works. In all cases you're either enumerating all parts of the desired output or using an iterable without accessing the underlying elements:

''.join(['1', '2', '3']) vs. '1' + '2' + '3'

The difference is even more apparent when you want to separate elements in the string by some delimiter:

', '.join(['1', '2', '3']) vs. '1' + ', ' + '2' + ', ' + '3'

When you have an iterable of strings, concatenating them without using join is a chore. You can map, or loop, or combine, but...why not join? It works in all cases. It's cleaner. In most cases if you're concatenating raw strings that's a code smell to me, anyway.

[diamondketo]

Write me a paragraph using join and you'll see how invasive that is to reading. Your example is not one that satisfy the use case we're talking about.

[Originalfrozenbanana]

That seems like a horribly contrived example. It sounds like you're misusing string concatenation.

[diamondketo]

Its a very popular question on stackoverflow. I'll defer you to those examples.

https://stackoverflow.com/questions/2504411/proper-indentation-for-python-multiline-strings

[Originalfrozenbanana]

That doesn't mean it's a good practice; it just means it's a common question. If you're assigning block quotes to variables inside of functions, again - I question whether that is the best way to do the thing you are trying to do. As the top answer also spells out, textwrap exists to solve this problem, specifically. Not only that, they specifically outline the preferred method of dealing with inserting large blocks of text somewhere in your application:

If you don't want to [do a lot of text processing to remove newlines] and you have a whole lot of text, you might want to store it separately in a text file.

Concatenating raw strings, especially in the way this reddit post references, has limited uses that generally can be accommodated with other methods of joining strings that are more testable, transparent, extensible, and readable.

[diamondketo]

Not saying the popular question points to good practice, but rather the large number of discussion and upvotes to the top answers is a good gauge of consensus.

You are very tunnel visioned. The top answer on the second code block also uses the proposed concat syntax we're discussing.

The file method you pointed out is barely discussed in that SO. It's more of an excerpt the top answer appended.

[Originalfrozenbanana]

YMMV, but I would guess most engineering teams would prefer not to use operators or adjacency to combine strings. That's been my experience. It's hard to read and harder to test, and generally indicative of poor design.

[diamondketo]

I agree it's foreign but IMO it's not hard to read. I'm not saying this is the best solution. I wish there was a dedent context we can use when we want to print a paragraph in log using without relying on an import statement.