On Feb 12, 2020, at 06:11, [email protected] wrote:
>
> I would like if the DictWriter would be able to write escape characters (\n
> and \r and their combinations such as \n\n\n and \r\n) as literal characters.
I don’t think you’re asking to write escape sequences, but how to write actual
newline and carriage return characters by escaping them. Thats what the strings
in your example post text have, at least. In a string literal, "a\nb" is the
three characters a, newline, b; the string literal "a\\nb" is the four
character a, backslash, n, b In your comments, you seem to have a lot of
confusion about the difference between Python string literals, JSON string
encodings, and the underlying strings, so it’s hard to be sure, but I’m about
90% sure that your actual strings have newlines, not backslash-escaped newlines.
But regardless of what you actually have, there’s no reason the csv module
should be changed to help you with this. It’s meant to write data in the same
language used by Excel (or some other known CSV dialect). There is no backslash
escaping of control characters in Excel—as is obvious from the fact that Excel
shows a \n as literally a backslash and an n rather than a newline within the
cell. If there’s some other CSV dialect that does use backslash escaping that
you want to support, that would be different—but you’re trying to use Excel, so
that can’t be the issue. The csv module doesn’t help you do web percent
encoding or rot13 encryption or reversing every other string because those are
meaningless to Excel and other CSV dialects, and the same is true here.
But that’s fine. You can already arbitrarily transform strings in Python,
before passing them to the csv module. For example, instead of
`c.writerow(row)` you can do `c.writerow(map(transformer, row))`, and you’re
done. That transformer could be an existing escaping function that means
exactly what you want, or you could write it yourself as a one-liner (`return
value.replace('\r', '\\r').replace('\n', '\\n')`).
Also, even if you disagree and think the csv module does need to change, you
need to explain what that change is. Would you add a new Dialect attribute?
What would it be? Would it share the same escapechar used for escaping quotes,
or have a different attribute, or be hardcoded to backslash? And so on.
> I asked a question about this on Stack Overflow but have had no good answers
> yet.
You got comments telling you to use str.replace to modify the strings as you
read them or as you write them. Which is the right answer. Your reply was that
you don’t have permission to modify the text. So you’re asking for is a way to
modify the text without modifying the text, which is obviously impossible. If
that’s true, then even if Python 3.9 added your requested feature and you
waited until it came out before continuing your project, you still wouldn’t be
able to use it, because if you don’t have permission to replace newlines with
\n escapes then you don’t have permission to ask the csv module to do it
either. So no wonder you haven’t gotten any good answers. If you asked how to
encode some text in UTF-16 and then said you don’t have permission to encode
the text, you’d get the same result—either no answers, or bad answers from
people who don’t know anything but are desperate for points so they just guess
wildly at something that might be kind of similar to what you want.
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