n00b question on spacing

[Ben Finney]

"Yves S. Garret" <yoursurrogategod at gmail.com> writes:

> I have the following line of code:
> log.msg("Item wrote to MongoDB database %s/%s" %(settings['MONGODB_DB'],
> settings['MONGODB_COLLECTION']), level=log.DEBUG, spider=spider)
[…]

> Is this ok? Are there any rules in Python when it comes to breaking up
> long lines of code?

PEP 8 is the common denominator; follow its restrictions and your code
will be a lot more readable to just about any Python programmer. So,
indent 4 columns for block structure, preferably 8 columns for
continuation lines, put spaces around binary operators, etc.

As for *where* to break long lines: I prefer the continuation lines to
be a standard indentation (4 or 8 columns), which means the indentation
doesn't need to change when the first line changes later. So I break at
an open paren, brace, bracket (‘(’, ‘{’, ‘[’) etc. and allow Python to
automatically continue the statement until that bracketing is closed.

    log.msg(
            "Item wrote to MongoDB database %s/%s"
                % (settings['MONGODB_DB'], settings['MONGODB_COLLECTION']),
            level=log.DEBUG, spider=spider)

That way, if the first line changes later, you don't need to change any
of the indentation on the continuation lines:

    logger.info(
            "Item wrote to MongoDB database %s/%s"
                % (settings['MONGODB_DB'], settings['MONGODB_COLLECTION']),
            level=log.DEBUG, spider=spider)

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Ben Finney